KILLED
proof of input_EU1RpNuVc0.trs
# AProVE Commit ID: aff8ecad908e01718a4c36e68d2e55d5e0f16e15 fuhs 20220216 unpublished


The Runtime Complexity (parallel-innermost) of the given CpxTRS could be proven to be BOUNDS(1, INF).

(0) CpxTRS
(1) RenamingProof [BOTH BOUNDS(ID, ID), 0 ms]
(2) CpxTRS
(3) RelTrsToTrsProof [UPPER BOUND(ID), 0 ms]
(4) CpxTRS
(5) CpxTrsToCdtProof [BOTH BOUNDS(ID, ID), 0 ms]
(6) CdtProblem
    (7) CdtToCpxRelTrsProof [BOTH BOUNDS(ID, ID), 0 ms]
    (8) CpxRelTRS
    (9) RenamingProof [BOTH BOUNDS(ID, ID), 0 ms]
    (10) CpxRelTRS
        (11) TypeInferenceProof [BOTH BOUNDS(ID, ID), 0 ms]
        (12) typed CpxTrs
        (13) OrderProof [LOWER BOUND(ID), 0 ms]
        (14) typed CpxTrs
    (15) RelTrsToDecreasingLoopProblemProof [LOWER BOUND(ID), 0 ms]
    (16) TRS for Loop Detection
(17) RelTrsToWeightedTrsProof [UPPER BOUND(ID), 0 ms]
(18) CpxWeightedTrs
    (19) TypeInferenceProof [BOTH BOUNDS(ID, ID), 0 ms]
    (20) CpxTypedWeightedTrs
    (21) CompletionProof [UPPER BOUND(ID), 0 ms]
    (22) CpxTypedWeightedCompleteTrs
        (23) CpxTypedWeightedTrsToRntsProof [UPPER BOUND(ID), 0 ms]
        (24) CpxRNTS
    (25) CompletionProof [UPPER BOUND(ID), 0 ms]
    (26) CpxTypedWeightedCompleteTrs
        (27) NarrowingProof [BOTH BOUNDS(ID, ID), 717 ms]
        (28) CpxTypedWeightedCompleteTrs
        (29) CpxTypedWeightedTrsToRntsProof [UPPER BOUND(ID), 0 ms]
        (30) CpxRNTS
        (31) InliningProof [UPPER BOUND(ID), 1526 ms]
        (32) CpxRNTS
        (33) SimplificationProof [BOTH BOUNDS(ID, ID), 22 ms]
        (34) CpxRNTS
        (35) CpxRntsAnalysisOrderProof [BOTH BOUNDS(ID, ID), 0 ms]
        (36) CpxRNTS
        (37) ResultPropagationProof [UPPER BOUND(ID), 0 ms]
        (38) CpxRNTS
        (39) IntTrsBoundProof [UPPER BOUND(ID), 153 ms]
        (40) CpxRNTS
        (41) IntTrsBoundProof [UPPER BOUND(ID), 57 ms]
        (42) CpxRNTS
        (43) ResultPropagationProof [UPPER BOUND(ID), 0 ms]
        (44) CpxRNTS
        (45) IntTrsBoundProof [UPPER BOUND(ID), 102 ms]
        (46) CpxRNTS
        (47) IntTrsBoundProof [UPPER BOUND(ID), 3 ms]
        (48) CpxRNTS
        (49) ResultPropagationProof [UPPER BOUND(ID), 0 ms]
        (50) CpxRNTS
        (51) IntTrsBoundProof [UPPER BOUND(ID), 273 ms]
        (52) CpxRNTS
        (53) IntTrsBoundProof [UPPER BOUND(ID), 65 ms]
        (54) CpxRNTS
        (55) ResultPropagationProof [UPPER BOUND(ID), 0 ms]
        (56) CpxRNTS
        (57) IntTrsBoundProof [UPPER BOUND(ID), 132 ms]
        (58) CpxRNTS
        (59) IntTrsBoundProof [UPPER BOUND(ID), 14 ms]
        (60) CpxRNTS
        (61) ResultPropagationProof [UPPER BOUND(ID), 0 ms]
        (62) CpxRNTS
        (63) IntTrsBoundProof [UPPER BOUND(ID), 110 ms]
        (64) CpxRNTS
        (65) IntTrsBoundProof [UPPER BOUND(ID), 54 ms]
        (66) CpxRNTS
        (67) ResultPropagationProof [UPPER BOUND(ID), 0 ms]
        (68) CpxRNTS
        (69) IntTrsBoundProof [UPPER BOUND(ID), 60.8 s]
        (70) CpxRNTS
        (71) IntTrsBoundProof [UPPER BOUND(ID), 29.7 s]
        (72) CpxRNTS
(73) CpxTrsToCdtProof [UPPER BOUND(ID), 0 ms]
(74) CdtProblem
    (75) CdtLeafRemovalProof [ComplexityIfPolyImplication, 0 ms]
    (76) CdtProblem
    (77) CdtRhsSimplificationProcessorProof [BOTH BOUNDS(ID, ID), 0 ms]
    (78) CdtProblem
    (79) CdtUsableRulesProof [BOTH BOUNDS(ID, ID), 6 ms]
    (80) CdtProblem
    (81) CdtToCpxRelTrsProof [BOTH BOUNDS(ID, ID), 0 ms]
    (82) CpxRelTRS
        (83) RelTrsToTrsProof [UPPER BOUND(ID), 0 ms]
        (84) CpxTRS
        (85) RelTrsToWeightedTrsProof [BOTH BOUNDS(ID, ID), 0 ms]
        (86) CpxWeightedTrs
            (87) TypeInferenceProof [BOTH BOUNDS(ID, ID), 0 ms]
            (88) CpxTypedWeightedTrs
            (89) CompletionProof [UPPER BOUND(ID), 0 ms]
            (90) CpxTypedWeightedCompleteTrs
            (91) CompletionProof [UPPER BOUND(ID), 0 ms]
            (92) CpxTypedWeightedCompleteTrs
                (93) CpxTypedWeightedTrsToRntsProof [UPPER BOUND(ID), 0 ms]
                (94) CpxRNTS
    (95) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 3 ms]
    (96) CdtProblem
        (97) CdtRhsSimplificationProcessorProof [BOTH BOUNDS(ID, ID), 0 ms]
        (98) CdtProblem
        (99) CdtRuleRemovalProof [UPPER BOUND(ADD(n^1)), 166 ms]
        (100) CdtProblem
        (101) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 0 ms]
        (102) CdtProblem
        (103) CdtLeafRemovalProof [BOTH BOUNDS(ID, ID), 0 ms]
        (104) CdtProblem
        (105) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 0 ms]
        (106) CdtProblem
        (107) CdtLeafRemovalProof [BOTH BOUNDS(ID, ID), 0 ms]
        (108) CdtProblem
        (109) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 0 ms]
        (110) CdtProblem
        (111) CdtLeafRemovalProof [BOTH BOUNDS(ID, ID), 0 ms]
        (112) CdtProblem
        (113) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 0 ms]
        (114) CdtProblem
        (115) CdtLeafRemovalProof [BOTH BOUNDS(ID, ID), 0 ms]
        (116) CdtProblem
        (117) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 0 ms]
        (118) CdtProblem
        (119) CdtLeafRemovalProof [BOTH BOUNDS(ID, ID), 0 ms]
        (120) CdtProblem
        (121) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 0 ms]
        (122) CdtProblem
        (123) CdtLeafRemovalProof [BOTH BOUNDS(ID, ID), 0 ms]
        (124) CdtProblem
        (125) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 0 ms]
        (126) CdtProblem
        (127) CdtLeafRemovalProof [BOTH BOUNDS(ID, ID), 0 ms]
        (128) CdtProblem
        (129) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 0 ms]
        (130) CdtProblem
        (131) CdtLeafRemovalProof [BOTH BOUNDS(ID, ID), 0 ms]
        (132) CdtProblem
        (133) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 0 ms]
        (134) CdtProblem
        (135) CdtRhsSimplificationProcessorProof [BOTH BOUNDS(ID, ID), 0 ms]
        (136) CdtProblem
        (137) CdtRuleRemovalProof [UPPER BOUND(ADD(n^1)), 743 ms]
        (138) CdtProblem
        (139) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 0 ms]
        (140) CdtProblem
        (141) CdtRhsSimplificationProcessorProof [BOTH BOUNDS(ID, ID), 0 ms]
        (142) CdtProblem
        (143) CdtKnowledgeProof [BOTH BOUNDS(ID, ID), 0 ms]
        (144) CdtProblem
        (145) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 0 ms]
        (146) CdtProblem
        (147) CdtRhsSimplificationProcessorProof [BOTH BOUNDS(ID, ID), 0 ms]
        (148) CdtProblem
        (149) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 0 ms]
        (150) CdtProblem
        (151) CdtRhsSimplificationProcessorProof [BOTH BOUNDS(ID, ID), 0 ms]
        (152) CdtProblem
        (153) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 0 ms]
        (154) CdtProblem
        (155) CdtRhsSimplificationProcessorProof [BOTH BOUNDS(ID, ID), 0 ms]
        (156) CdtProblem
        (157) CdtKnowledgeProof [BOTH BOUNDS(ID, ID), 0 ms]
        (158) CdtProblem
        (159) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 0 ms]
        (160) CdtProblem
        (161) CdtRhsSimplificationProcessorProof [BOTH BOUNDS(ID, ID), 0 ms]
        (162) CdtProblem
        (163) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 0 ms]
        (164) CdtProblem
        (165) CdtRhsSimplificationProcessorProof [BOTH BOUNDS(ID, ID), 0 ms]
        (166) CdtProblem
        (167) CdtKnowledgeProof [BOTH BOUNDS(ID, ID), 0 ms]
        (168) CdtProblem
        (169) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 9 ms]
        (170) CdtProblem
        (171) CdtRhsSimplificationProcessorProof [BOTH BOUNDS(ID, ID), 0 ms]
        (172) CdtProblem
        (173) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 8 ms]
        (174) CdtProblem
        (175) CdtRhsSimplificationProcessorProof [BOTH BOUNDS(ID, ID), 0 ms]
        (176) CdtProblem
        (177) CdtKnowledgeProof [BOTH BOUNDS(ID, ID), 0 ms]
        (178) CdtProblem
        (179) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 0 ms]
        (180) CdtProblem
        (181) CdtRhsSimplificationProcessorProof [BOTH BOUNDS(ID, ID), 0 ms]
        (182) CdtProblem
        (183) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 0 ms]
        (184) CdtProblem
        (185) CdtRhsSimplificationProcessorProof [BOTH BOUNDS(ID, ID), 0 ms]
        (186) CdtProblem
        (187) CdtKnowledgeProof [BOTH BOUNDS(ID, ID), 0 ms]
        (188) CdtProblem
        (189) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 9 ms]
        (190) CdtProblem
        (191) CdtRhsSimplificationProcessorProof [BOTH BOUNDS(ID, ID), 0 ms]
        (192) CdtProblem
        (193) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 9 ms]
        (194) CdtProblem
        (195) CdtRhsSimplificationProcessorProof [BOTH BOUNDS(ID, ID), 0 ms]
        (196) CdtProblem
        (197) CdtKnowledgeProof [BOTH BOUNDS(ID, ID), 0 ms]
        (198) CdtProblem
        (199) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 8 ms]
        (200) CdtProblem
        (201) CdtRhsSimplificationProcessorProof [BOTH BOUNDS(ID, ID), 0 ms]
        (202) CdtProblem
        (203) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 0 ms]
        (204) CdtProblem
        (205) CdtRhsSimplificationProcessorProof [BOTH BOUNDS(ID, ID), 0 ms]
        (206) CdtProblem
        (207) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 0 ms]
        (208) CdtProblem
        (209) CdtLeafRemovalProof [BOTH BOUNDS(ID, ID), 0 ms]
        (210) CdtProblem
        (211) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 14 ms]
        (212) CdtProblem
        (213) CdtLeafRemovalProof [BOTH BOUNDS(ID, ID), 0 ms]
        (214) CdtProblem
        (215) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 6 ms]
        (216) CdtProblem
        (217) CdtLeafRemovalProof [BOTH BOUNDS(ID, ID), 0 ms]
        (218) CdtProblem
        (219) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 0 ms]
        (220) CdtProblem
        (221) CdtLeafRemovalProof [BOTH BOUNDS(ID, ID), 0 ms]
        (222) CdtProblem
        (223) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 12 ms]
        (224) CdtProblem
        (225) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 0 ms]
        (226) CdtProblem
        (227) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 0 ms]
        (228) CdtProblem
        (229) CdtLeafRemovalProof [BOTH BOUNDS(ID, ID), 0 ms]
        (230) CdtProblem
        (231) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 0 ms]
        (232) CdtProblem
        (233) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 0 ms]
        (234) CdtProblem
        (235) CdtLeafRemovalProof [BOTH BOUNDS(ID, ID), 0 ms]
        (236) CdtProblem
        (237) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 0 ms]
        (238) CdtProblem
        (239) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 0 ms]
        (240) CdtProblem
        (241) CdtLeafRemovalProof [BOTH BOUNDS(ID, ID), 0 ms]
        (242) CdtProblem
        (243) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 12 ms]
        (244) CdtProblem
        (245) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 0 ms]
        (246) CdtProblem
        (247) CdtLeafRemovalProof [BOTH BOUNDS(ID, ID), 0 ms]
        (248) CdtProblem
        (249) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 0 ms]
        (250) CdtProblem
        (251) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 17 ms]
        (252) CdtProblem
        (253) CdtLeafRemovalProof [BOTH BOUNDS(ID, ID), 0 ms]
        (254) CdtProblem
        (255) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 0 ms]
        (256) CdtProblem
        (257) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 0 ms]
        (258) CdtProblem
        (259) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 0 ms]
        (260) CdtProblem
        (261) CdtLeafRemovalProof [BOTH BOUNDS(ID, ID), 0 ms]
        (262) CdtProblem
        (263) CdtNarrowingProof [BOTH BOUNDS(ID, ID), 0 ms]
        (264) CdtProblem
        (265) CdtLeafRemovalProof [BOTH BOUNDS(ID, ID), 0 ms]
        (266) CdtProblem


----------------------------------------

(0)
Obligation:
The Runtime Complexity (parallel-innermost) of the given CpxTRS could be proven to be BOUNDS(1, INF).


The TRS R consists of the following rules:

   isEmpty(empty) -> true
   isEmpty(node(l, x, r)) -> false
   left(empty) -> empty
   left(node(l, x, r)) -> l
   right(empty) -> empty
   right(node(l, x, r)) -> r
   elem(node(l, x, r)) -> x
   append(nil, x) -> cons(x, nil)
   append(cons(y, ys), x) -> cons(y, append(ys, x))
   listify(n, xs) -> if(isEmpty(n), isEmpty(left(n)), right(n), node(left(left(n)), elem(left(n)), node(right(left(n)), elem(n), right(n))), xs, append(xs, n))
   if(true, b, n, m, xs, ys) -> xs
   if(false, false, n, m, xs, ys) -> listify(m, xs)
   if(false, true, n, m, xs, ys) -> listify(n, ys)
   toList(n) -> listify(n, nil)

S is empty.
Rewrite Strategy: PARALLEL_INNERMOST
----------------------------------------

(1) RenamingProof (BOTH BOUNDS(ID, ID))
Renamed function symbols to avoid clashes with predefined symbol.
----------------------------------------

(2)
Obligation:
The Runtime Complexity (parallel-innermost) of the given CpxTRS could be proven to be BOUNDS(1, INF).


The TRS R consists of the following rules:

   isEmpty(empty) -> true
   isEmpty(node(l, x, r)) -> false
   left(empty) -> empty
   left(node(l, x, r)) -> l
   right(empty) -> empty
   right(node(l, x, r)) -> r
   elem(node(l, x, r)) -> x
   append(nil, x) -> cons(x, nil)
   append(cons(y, ys), x) -> cons(y, append(ys, x))
   listify(n, xs) -> if(isEmpty(n), isEmpty(left(n)), right(n), node(left(left(n)), elem(left(n)), node(right(left(n)), elem(n), right(n))), xs, append(xs, n))
   if(true, b, n, m, xs, ys) -> xs
   if(false, false, n, m, xs, ys) -> listify(m, xs)
   if(false, true, n, m, xs, ys) -> listify(n, ys)
   toList(n) -> listify(n, nil)

S is empty.
Rewrite Strategy: PARALLEL_INNERMOST
----------------------------------------

(3) RelTrsToTrsProof (UPPER BOUND(ID))
transformed relative TRS to TRS
----------------------------------------

(4)
Obligation:
The Runtime Complexity (parallel-innermost) of the given CpxTRS could be proven to be BOUNDS(1, INF).


The TRS R consists of the following rules:

   isEmpty(empty) -> true
   isEmpty(node(l, x, r)) -> false
   left(empty) -> empty
   left(node(l, x, r)) -> l
   right(empty) -> empty
   right(node(l, x, r)) -> r
   elem(node(l, x, r)) -> x
   append(nil, x) -> cons(x, nil)
   append(cons(y, ys), x) -> cons(y, append(ys, x))
   listify(n, xs) -> if(isEmpty(n), isEmpty(left(n)), right(n), node(left(left(n)), elem(left(n)), node(right(left(n)), elem(n), right(n))), xs, append(xs, n))
   if(true, b, n, m, xs, ys) -> xs
   if(false, false, n, m, xs, ys) -> listify(m, xs)
   if(false, true, n, m, xs, ys) -> listify(n, ys)
   toList(n) -> listify(n, nil)

S is empty.
Rewrite Strategy: PARALLEL_INNERMOST
----------------------------------------

(5) CpxTrsToCdtProof (BOTH BOUNDS(ID, ID))
Converted Cpx (relative) TRS with rewrite strategy PARALLEL_INNERMOST to CDT
----------------------------------------

(6)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
   listify(z0, z1) -> if(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))
   if(true, z0, z1, z2, z3, z4) -> z3
   if(false, false, z0, z1, z2, z3) -> listify(z1, z2)
   if(false, true, z0, z1, z2, z3) -> listify(z0, z3)
   toList(z0) -> listify(z0, nil)
Tuples:
   ISEMPTY(empty) -> c
   ISEMPTY(node(z0, z1, z2)) -> c1
   LEFT(empty) -> c2
   LEFT(node(z0, z1, z2)) -> c3
   RIGHT(empty) -> c4
   RIGHT(node(z0, z1, z2)) -> c5
   ELEM(node(z0, z1, z2)) -> c6
   APPEND(nil, z0) -> c7
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   LISTIFY(z0, z1) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ISEMPTY(z0))
   LISTIFY(z0, z1) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ISEMPTY(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), RIGHT(z0))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), LEFT(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ELEM(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), RIGHT(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ELEM(z0))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), RIGHT(z0))
   LISTIFY(z0, z1) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), APPEND(z1, z0))
   IF(true, z0, z1, z2, z3, z4) -> c18
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   TOLIST(z0) -> c21(LISTIFY(z0, nil))
S tuples:
   ISEMPTY(empty) -> c
   ISEMPTY(node(z0, z1, z2)) -> c1
   LEFT(empty) -> c2
   LEFT(node(z0, z1, z2)) -> c3
   RIGHT(empty) -> c4
   RIGHT(node(z0, z1, z2)) -> c5
   ELEM(node(z0, z1, z2)) -> c6
   APPEND(nil, z0) -> c7
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   LISTIFY(z0, z1) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ISEMPTY(z0))
   LISTIFY(z0, z1) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ISEMPTY(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), RIGHT(z0))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), LEFT(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ELEM(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), RIGHT(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ELEM(z0))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), RIGHT(z0))
   LISTIFY(z0, z1) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), APPEND(z1, z0))
   IF(true, z0, z1, z2, z3, z4) -> c18
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   TOLIST(z0) -> c21(LISTIFY(z0, nil))
K tuples:none
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2, listify_2, if_6, toList_1

Defined Pair Symbols:   ISEMPTY_1, LEFT_1, RIGHT_1, ELEM_1, APPEND_2, LISTIFY_2, IF_6, TOLIST_1

Compound Symbols:   c, c1, c2, c3, c4, c5, c6, c7, c8_1, c9_2, c10_3, c11_2, c12_3, c13_3, c14_3, c15_2, c16_2, c17_2, c18, c19_1, c20_1, c21_1


----------------------------------------

(7) CdtToCpxRelTrsProof (BOTH BOUNDS(ID, ID))
Converted S to standard rules, and D \ S as well as R to relative rules.
----------------------------------------

(8)
Obligation:
The Runtime Complexity (innermost) of the given CpxRelTRS could be proven to be BOUNDS(1, INF).


The TRS R consists of the following rules:

   ISEMPTY(empty) -> c
   ISEMPTY(node(z0, z1, z2)) -> c1
   LEFT(empty) -> c2
   LEFT(node(z0, z1, z2)) -> c3
   RIGHT(empty) -> c4
   RIGHT(node(z0, z1, z2)) -> c5
   ELEM(node(z0, z1, z2)) -> c6
   APPEND(nil, z0) -> c7
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   LISTIFY(z0, z1) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ISEMPTY(z0))
   LISTIFY(z0, z1) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ISEMPTY(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), RIGHT(z0))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), LEFT(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ELEM(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), RIGHT(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ELEM(z0))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), RIGHT(z0))
   LISTIFY(z0, z1) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), APPEND(z1, z0))
   IF(true, z0, z1, z2, z3, z4) -> c18
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   TOLIST(z0) -> c21(LISTIFY(z0, nil))

The (relative) TRS S consists of the following rules:

   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
   listify(z0, z1) -> if(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))
   if(true, z0, z1, z2, z3, z4) -> z3
   if(false, false, z0, z1, z2, z3) -> listify(z1, z2)
   if(false, true, z0, z1, z2, z3) -> listify(z0, z3)
   toList(z0) -> listify(z0, nil)

Rewrite Strategy: INNERMOST
----------------------------------------

(9) RenamingProof (BOTH BOUNDS(ID, ID))
Renamed function symbols to avoid clashes with predefined symbol.
----------------------------------------

(10)
Obligation:
The Runtime Complexity (innermost) of the given CpxRelTRS could be proven to be BOUNDS(1, INF).


The TRS R consists of the following rules:

   ISEMPTY(empty) -> c
   ISEMPTY(node(z0, z1, z2)) -> c1
   LEFT(empty) -> c2
   LEFT(node(z0, z1, z2)) -> c3
   RIGHT(empty) -> c4
   RIGHT(node(z0, z1, z2)) -> c5
   ELEM(node(z0, z1, z2)) -> c6
   APPEND(nil, z0) -> c7
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   LISTIFY(z0, z1) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ISEMPTY(z0))
   LISTIFY(z0, z1) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ISEMPTY(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), RIGHT(z0))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), LEFT(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ELEM(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), RIGHT(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ELEM(z0))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), RIGHT(z0))
   LISTIFY(z0, z1) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), APPEND(z1, z0))
   IF(true, z0, z1, z2, z3, z4) -> c18
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   TOLIST(z0) -> c21(LISTIFY(z0, nil))

The (relative) TRS S consists of the following rules:

   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
   listify(z0, z1) -> if(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))
   if(true, z0, z1, z2, z3, z4) -> z3
   if(false, false, z0, z1, z2, z3) -> listify(z1, z2)
   if(false, true, z0, z1, z2, z3) -> listify(z0, z3)
   toList(z0) -> listify(z0, nil)

Rewrite Strategy: INNERMOST
----------------------------------------

(11) TypeInferenceProof (BOTH BOUNDS(ID, ID))
Inferred types.
----------------------------------------

(12)
Obligation:
Innermost TRS:
Rules:
ISEMPTY(empty) -> c
ISEMPTY(node(z0, z1, z2)) -> c1
LEFT(empty) -> c2
LEFT(node(z0, z1, z2)) -> c3
RIGHT(empty) -> c4
RIGHT(node(z0, z1, z2)) -> c5
ELEM(node(z0, z1, z2)) -> c6
APPEND(nil, z0) -> c7
APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
LISTIFY(z0, z1) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ISEMPTY(z0))
LISTIFY(z0, z1) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ISEMPTY(left(z0)), LEFT(z0))
LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), RIGHT(z0))
LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), LEFT(left(z0)), LEFT(z0))
LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ELEM(left(z0)), LEFT(z0))
LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), RIGHT(left(z0)), LEFT(z0))
LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ELEM(z0))
LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), RIGHT(z0))
LISTIFY(z0, z1) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), APPEND(z1, z0))
IF(true, z0, z1, z2, z3, z4) -> c18
IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
TOLIST(z0) -> c21(LISTIFY(z0, nil))
isEmpty(empty) -> true
isEmpty(node(z0, z1, z2)) -> false
left(empty) -> empty
left(node(z0, z1, z2)) -> z0
right(empty) -> empty
right(node(z0, z1, z2)) -> z2
elem(node(z0, z1, z2)) -> z1
append(nil, z0) -> cons(z0, nil)
append(cons(y, z0), z1) -> cons(y, append(z0, z1))
listify(z0, z1) -> if(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))
if(true, z0, z1, z2, z3, z4) -> z3
if(false, false, z0, z1, z2, z3) -> listify(z1, z2)
if(false, true, z0, z1, z2, z3) -> listify(z0, z3)
toList(z0) -> listify(z0, nil)

Types:
ISEMPTY :: empty:node:y -> c:c1
empty :: empty:node:y
c :: c:c1
node :: empty:node:y -> elem -> empty:node:y -> empty:node:y
c1 :: c:c1
LEFT :: empty:node:y -> c2:c3
c2 :: c2:c3
c3 :: c2:c3
RIGHT :: empty:node:y -> c4:c5
c4 :: c4:c5
c5 :: c4:c5
ELEM :: empty:node:y -> c6
c6 :: c6
APPEND :: nil:cons -> empty:node:y -> c7:c8
nil :: nil:cons
c7 :: c7:c8
cons :: empty:node:y -> nil:cons -> nil:cons
y :: empty:node:y
c8 :: c7:c8 -> c7:c8
LISTIFY :: empty:node:y -> nil:cons -> c9:c10:c11:c12:c13:c14:c15:c16:c17
c9 :: c18:c19:c20 -> c:c1 -> c9:c10:c11:c12:c13:c14:c15:c16:c17
IF :: true:false -> true:false -> empty:node:y -> empty:node:y -> nil:cons -> nil:cons -> c18:c19:c20
isEmpty :: empty:node:y -> true:false
left :: empty:node:y -> empty:node:y
right :: empty:node:y -> empty:node:y
elem :: empty:node:y -> elem
append :: nil:cons -> empty:node:y -> nil:cons
c10 :: c18:c19:c20 -> c:c1 -> c2:c3 -> c9:c10:c11:c12:c13:c14:c15:c16:c17
c11 :: c18:c19:c20 -> c4:c5 -> c9:c10:c11:c12:c13:c14:c15:c16:c17
c12 :: c18:c19:c20 -> c2:c3 -> c2:c3 -> c9:c10:c11:c12:c13:c14:c15:c16:c17
c13 :: c18:c19:c20 -> c6 -> c2:c3 -> c9:c10:c11:c12:c13:c14:c15:c16:c17
c14 :: c18:c19:c20 -> c4:c5 -> c2:c3 -> c9:c10:c11:c12:c13:c14:c15:c16:c17
c15 :: c18:c19:c20 -> c6 -> c9:c10:c11:c12:c13:c14:c15:c16:c17
c16 :: c18:c19:c20 -> c4:c5 -> c9:c10:c11:c12:c13:c14:c15:c16:c17
c17 :: c18:c19:c20 -> c7:c8 -> c9:c10:c11:c12:c13:c14:c15:c16:c17
true :: true:false
c18 :: c18:c19:c20
false :: true:false
c19 :: c9:c10:c11:c12:c13:c14:c15:c16:c17 -> c18:c19:c20
c20 :: c9:c10:c11:c12:c13:c14:c15:c16:c17 -> c18:c19:c20
TOLIST :: empty:node:y -> c21
c21 :: c9:c10:c11:c12:c13:c14:c15:c16:c17 -> c21
listify :: empty:node:y -> nil:cons -> nil:cons
if :: true:false -> true:false -> empty:node:y -> empty:node:y -> nil:cons -> nil:cons -> nil:cons
toList :: empty:node:y -> nil:cons
hole_c:c11_22 :: c:c1
hole_empty:node:y2_22 :: empty:node:y
hole_elem3_22 :: elem
hole_c2:c34_22 :: c2:c3
hole_c4:c55_22 :: c4:c5
hole_c66_22 :: c6
hole_c7:c87_22 :: c7:c8
hole_nil:cons8_22 :: nil:cons
hole_c9:c10:c11:c12:c13:c14:c15:c16:c179_22 :: c9:c10:c11:c12:c13:c14:c15:c16:c17
hole_c18:c19:c2010_22 :: c18:c19:c20
hole_true:false11_22 :: true:false
hole_c2112_22 :: c21
gen_empty:node:y13_22 :: Nat -> empty:node:y
gen_c7:c814_22 :: Nat -> c7:c8
gen_nil:cons15_22 :: Nat -> nil:cons

----------------------------------------

(13) OrderProof (LOWER BOUND(ID))
Heuristically decided to analyse the following defined symbols:
APPEND, LISTIFY, append, listify

They will be analysed ascendingly in the following order:
APPEND < LISTIFY
append < LISTIFY
append < listify

----------------------------------------

(14)
Obligation:
Innermost TRS:
Rules:
ISEMPTY(empty) -> c
ISEMPTY(node(z0, z1, z2)) -> c1
LEFT(empty) -> c2
LEFT(node(z0, z1, z2)) -> c3
RIGHT(empty) -> c4
RIGHT(node(z0, z1, z2)) -> c5
ELEM(node(z0, z1, z2)) -> c6
APPEND(nil, z0) -> c7
APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
LISTIFY(z0, z1) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ISEMPTY(z0))
LISTIFY(z0, z1) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ISEMPTY(left(z0)), LEFT(z0))
LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), RIGHT(z0))
LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), LEFT(left(z0)), LEFT(z0))
LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ELEM(left(z0)), LEFT(z0))
LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), RIGHT(left(z0)), LEFT(z0))
LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ELEM(z0))
LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), RIGHT(z0))
LISTIFY(z0, z1) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), APPEND(z1, z0))
IF(true, z0, z1, z2, z3, z4) -> c18
IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
TOLIST(z0) -> c21(LISTIFY(z0, nil))
isEmpty(empty) -> true
isEmpty(node(z0, z1, z2)) -> false
left(empty) -> empty
left(node(z0, z1, z2)) -> z0
right(empty) -> empty
right(node(z0, z1, z2)) -> z2
elem(node(z0, z1, z2)) -> z1
append(nil, z0) -> cons(z0, nil)
append(cons(y, z0), z1) -> cons(y, append(z0, z1))
listify(z0, z1) -> if(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))
if(true, z0, z1, z2, z3, z4) -> z3
if(false, false, z0, z1, z2, z3) -> listify(z1, z2)
if(false, true, z0, z1, z2, z3) -> listify(z0, z3)
toList(z0) -> listify(z0, nil)

Types:
ISEMPTY :: empty:node:y -> c:c1
empty :: empty:node:y
c :: c:c1
node :: empty:node:y -> elem -> empty:node:y -> empty:node:y
c1 :: c:c1
LEFT :: empty:node:y -> c2:c3
c2 :: c2:c3
c3 :: c2:c3
RIGHT :: empty:node:y -> c4:c5
c4 :: c4:c5
c5 :: c4:c5
ELEM :: empty:node:y -> c6
c6 :: c6
APPEND :: nil:cons -> empty:node:y -> c7:c8
nil :: nil:cons
c7 :: c7:c8
cons :: empty:node:y -> nil:cons -> nil:cons
y :: empty:node:y
c8 :: c7:c8 -> c7:c8
LISTIFY :: empty:node:y -> nil:cons -> c9:c10:c11:c12:c13:c14:c15:c16:c17
c9 :: c18:c19:c20 -> c:c1 -> c9:c10:c11:c12:c13:c14:c15:c16:c17
IF :: true:false -> true:false -> empty:node:y -> empty:node:y -> nil:cons -> nil:cons -> c18:c19:c20
isEmpty :: empty:node:y -> true:false
left :: empty:node:y -> empty:node:y
right :: empty:node:y -> empty:node:y
elem :: empty:node:y -> elem
append :: nil:cons -> empty:node:y -> nil:cons
c10 :: c18:c19:c20 -> c:c1 -> c2:c3 -> c9:c10:c11:c12:c13:c14:c15:c16:c17
c11 :: c18:c19:c20 -> c4:c5 -> c9:c10:c11:c12:c13:c14:c15:c16:c17
c12 :: c18:c19:c20 -> c2:c3 -> c2:c3 -> c9:c10:c11:c12:c13:c14:c15:c16:c17
c13 :: c18:c19:c20 -> c6 -> c2:c3 -> c9:c10:c11:c12:c13:c14:c15:c16:c17
c14 :: c18:c19:c20 -> c4:c5 -> c2:c3 -> c9:c10:c11:c12:c13:c14:c15:c16:c17
c15 :: c18:c19:c20 -> c6 -> c9:c10:c11:c12:c13:c14:c15:c16:c17
c16 :: c18:c19:c20 -> c4:c5 -> c9:c10:c11:c12:c13:c14:c15:c16:c17
c17 :: c18:c19:c20 -> c7:c8 -> c9:c10:c11:c12:c13:c14:c15:c16:c17
true :: true:false
c18 :: c18:c19:c20
false :: true:false
c19 :: c9:c10:c11:c12:c13:c14:c15:c16:c17 -> c18:c19:c20
c20 :: c9:c10:c11:c12:c13:c14:c15:c16:c17 -> c18:c19:c20
TOLIST :: empty:node:y -> c21
c21 :: c9:c10:c11:c12:c13:c14:c15:c16:c17 -> c21
listify :: empty:node:y -> nil:cons -> nil:cons
if :: true:false -> true:false -> empty:node:y -> empty:node:y -> nil:cons -> nil:cons -> nil:cons
toList :: empty:node:y -> nil:cons
hole_c:c11_22 :: c:c1
hole_empty:node:y2_22 :: empty:node:y
hole_elem3_22 :: elem
hole_c2:c34_22 :: c2:c3
hole_c4:c55_22 :: c4:c5
hole_c66_22 :: c6
hole_c7:c87_22 :: c7:c8
hole_nil:cons8_22 :: nil:cons
hole_c9:c10:c11:c12:c13:c14:c15:c16:c179_22 :: c9:c10:c11:c12:c13:c14:c15:c16:c17
hole_c18:c19:c2010_22 :: c18:c19:c20
hole_true:false11_22 :: true:false
hole_c2112_22 :: c21
gen_empty:node:y13_22 :: Nat -> empty:node:y
gen_c7:c814_22 :: Nat -> c7:c8
gen_nil:cons15_22 :: Nat -> nil:cons


Generator Equations:
gen_empty:node:y13_22(0) <=> empty
gen_empty:node:y13_22(+(x, 1)) <=> node(empty, hole_elem3_22, gen_empty:node:y13_22(x))
gen_c7:c814_22(0) <=> c7
gen_c7:c814_22(+(x, 1)) <=> c8(gen_c7:c814_22(x))
gen_nil:cons15_22(0) <=> nil
gen_nil:cons15_22(+(x, 1)) <=> cons(empty, gen_nil:cons15_22(x))


The following defined symbols remain to be analysed:
APPEND, LISTIFY, append, listify

They will be analysed ascendingly in the following order:
APPEND < LISTIFY
append < LISTIFY
append < listify

----------------------------------------

(15) RelTrsToDecreasingLoopProblemProof (LOWER BOUND(ID))
Transformed a relative TRS into a decreasing-loop problem.
----------------------------------------

(16)
Obligation:
Analyzing the following TRS for decreasing loops:

The Runtime Complexity (innermost) of the given CpxRelTRS could be proven to be BOUNDS(1, INF).


The TRS R consists of the following rules:

   ISEMPTY(empty) -> c
   ISEMPTY(node(z0, z1, z2)) -> c1
   LEFT(empty) -> c2
   LEFT(node(z0, z1, z2)) -> c3
   RIGHT(empty) -> c4
   RIGHT(node(z0, z1, z2)) -> c5
   ELEM(node(z0, z1, z2)) -> c6
   APPEND(nil, z0) -> c7
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   LISTIFY(z0, z1) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ISEMPTY(z0))
   LISTIFY(z0, z1) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ISEMPTY(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), RIGHT(z0))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), LEFT(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ELEM(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), RIGHT(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ELEM(z0))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), RIGHT(z0))
   LISTIFY(z0, z1) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), APPEND(z1, z0))
   IF(true, z0, z1, z2, z3, z4) -> c18
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   TOLIST(z0) -> c21(LISTIFY(z0, nil))

The (relative) TRS S consists of the following rules:

   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
   listify(z0, z1) -> if(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))
   if(true, z0, z1, z2, z3, z4) -> z3
   if(false, false, z0, z1, z2, z3) -> listify(z1, z2)
   if(false, true, z0, z1, z2, z3) -> listify(z0, z3)
   toList(z0) -> listify(z0, nil)

Rewrite Strategy: INNERMOST
----------------------------------------

(17) RelTrsToWeightedTrsProof (UPPER BOUND(ID))
Transformed relative TRS to weighted TRS
----------------------------------------

(18)
Obligation:
The Runtime Complexity (innermost) of the given CpxWeightedTrs could be proven to be BOUNDS(1, INF).


The TRS R consists of the following rules:

   isEmpty(empty) -> true [1]
   isEmpty(node(l, x, r)) -> false [1]
   left(empty) -> empty [1]
   left(node(l, x, r)) -> l [1]
   right(empty) -> empty [1]
   right(node(l, x, r)) -> r [1]
   elem(node(l, x, r)) -> x [1]
   append(nil, x) -> cons(x, nil) [1]
   append(cons(y, ys), x) -> cons(y, append(ys, x)) [1]
   listify(n, xs) -> if(isEmpty(n), isEmpty(left(n)), right(n), node(left(left(n)), elem(left(n)), node(right(left(n)), elem(n), right(n))), xs, append(xs, n)) [1]
   if(true, b, n, m, xs, ys) -> xs [1]
   if(false, false, n, m, xs, ys) -> listify(m, xs) [1]
   if(false, true, n, m, xs, ys) -> listify(n, ys) [1]
   toList(n) -> listify(n, nil) [1]

Rewrite Strategy: INNERMOST
----------------------------------------

(19) TypeInferenceProof (BOTH BOUNDS(ID, ID))
Infered types.
----------------------------------------

(20)
Obligation:
Runtime Complexity Weighted TRS with Types.
The TRS R consists of the following rules:

   isEmpty(empty) -> true [1]
   isEmpty(node(l, x, r)) -> false [1]
   left(empty) -> empty [1]
   left(node(l, x, r)) -> l [1]
   right(empty) -> empty [1]
   right(node(l, x, r)) -> r [1]
   elem(node(l, x, r)) -> x [1]
   append(nil, x) -> cons(x, nil) [1]
   append(cons(y, ys), x) -> cons(y, append(ys, x)) [1]
   listify(n, xs) -> if(isEmpty(n), isEmpty(left(n)), right(n), node(left(left(n)), elem(left(n)), node(right(left(n)), elem(n), right(n))), xs, append(xs, n)) [1]
   if(true, b, n, m, xs, ys) -> xs [1]
   if(false, false, n, m, xs, ys) -> listify(m, xs) [1]
   if(false, true, n, m, xs, ys) -> listify(n, ys) [1]
   toList(n) -> listify(n, nil) [1]

The TRS has the following type information:
isEmpty :: empty:node:y -> true:false
empty :: empty:node:y
true :: true:false
node :: empty:node:y -> elem -> empty:node:y -> empty:node:y
false :: true:false
left :: empty:node:y -> empty:node:y
right :: empty:node:y -> empty:node:y
elem :: empty:node:y -> elem
append :: nil:cons -> empty:node:y -> nil:cons
nil :: nil:cons
cons :: empty:node:y -> nil:cons -> nil:cons
y :: empty:node:y
listify :: empty:node:y -> nil:cons -> nil:cons
if :: true:false -> true:false -> empty:node:y -> empty:node:y -> nil:cons -> nil:cons -> nil:cons
toList :: empty:node:y -> nil:cons

Rewrite Strategy: INNERMOST
----------------------------------------

(21) CompletionProof (UPPER BOUND(ID))
The TRS is a completely defined constructor system, as every type has a constant constructor and the following rules were added:

   isEmpty(v0) -> null_isEmpty [0]
   left(v0) -> null_left [0]
   right(v0) -> null_right [0]
   elem(v0) -> null_elem [0]
   append(v0, v1) -> null_append [0]
   if(v0, v1, v2, v3, v4, v5) -> null_if [0]

And the following fresh constants:    null_isEmpty, null_left, null_right, null_elem, null_append, null_if

----------------------------------------

(22)
Obligation:
Runtime Complexity Weighted TRS where all functions are completely defined. The underlying TRS is:

Runtime Complexity Weighted TRS with Types.
The TRS R consists of the following rules:

   isEmpty(empty) -> true [1]
   isEmpty(node(l, x, r)) -> false [1]
   left(empty) -> empty [1]
   left(node(l, x, r)) -> l [1]
   right(empty) -> empty [1]
   right(node(l, x, r)) -> r [1]
   elem(node(l, x, r)) -> x [1]
   append(nil, x) -> cons(x, nil) [1]
   append(cons(y, ys), x) -> cons(y, append(ys, x)) [1]
   listify(n, xs) -> if(isEmpty(n), isEmpty(left(n)), right(n), node(left(left(n)), elem(left(n)), node(right(left(n)), elem(n), right(n))), xs, append(xs, n)) [1]
   if(true, b, n, m, xs, ys) -> xs [1]
   if(false, false, n, m, xs, ys) -> listify(m, xs) [1]
   if(false, true, n, m, xs, ys) -> listify(n, ys) [1]
   toList(n) -> listify(n, nil) [1]
   isEmpty(v0) -> null_isEmpty [0]
   left(v0) -> null_left [0]
   right(v0) -> null_right [0]
   elem(v0) -> null_elem [0]
   append(v0, v1) -> null_append [0]
   if(v0, v1, v2, v3, v4, v5) -> null_if [0]

The TRS has the following type information:
isEmpty :: empty:node:y:null_left:null_right -> true:false:null_isEmpty
empty :: empty:node:y:null_left:null_right
true :: true:false:null_isEmpty
node :: empty:node:y:null_left:null_right -> null_elem -> empty:node:y:null_left:null_right -> empty:node:y:null_left:null_right
false :: true:false:null_isEmpty
left :: empty:node:y:null_left:null_right -> empty:node:y:null_left:null_right
right :: empty:node:y:null_left:null_right -> empty:node:y:null_left:null_right
elem :: empty:node:y:null_left:null_right -> null_elem
append :: nil:cons:null_append:null_if -> empty:node:y:null_left:null_right -> nil:cons:null_append:null_if
nil :: nil:cons:null_append:null_if
cons :: empty:node:y:null_left:null_right -> nil:cons:null_append:null_if -> nil:cons:null_append:null_if
y :: empty:node:y:null_left:null_right
listify :: empty:node:y:null_left:null_right -> nil:cons:null_append:null_if -> nil:cons:null_append:null_if
if :: true:false:null_isEmpty -> true:false:null_isEmpty -> empty:node:y:null_left:null_right -> empty:node:y:null_left:null_right -> nil:cons:null_append:null_if -> nil:cons:null_append:null_if -> nil:cons:null_append:null_if
toList :: empty:node:y:null_left:null_right -> nil:cons:null_append:null_if
null_isEmpty :: true:false:null_isEmpty
null_left :: empty:node:y:null_left:null_right
null_right :: empty:node:y:null_left:null_right
null_elem :: null_elem
null_append :: nil:cons:null_append:null_if
null_if :: nil:cons:null_append:null_if

Rewrite Strategy: INNERMOST
----------------------------------------

(23) CpxTypedWeightedTrsToRntsProof (UPPER BOUND(ID))
Transformed the TRS into an over-approximating RNTS by (improved) Size Abstraction.
The constant constructors are abstracted as follows:

   empty => 0
   true => 2
   false => 1
   nil => 0
   y => 1
   null_isEmpty => 0
   null_left => 0
   null_right => 0
   null_elem => 0
   null_append => 0
   null_if => 0

----------------------------------------

(24)
Obligation:
Complexity RNTS consisting of the following rules:

   append(z, z') -{ 0 }-> 0 :|: v0 >= 0, v1 >= 0, z = v0, z' = v1
   append(z, z') -{ 1 }-> 1 + x + 0 :|: z' = x, x >= 0, z = 0
   append(z, z') -{ 1 }-> 1 + 1 + append(ys, x) :|: z' = x, ys >= 0, x >= 0, z = 1 + 1 + ys
   elem(z) -{ 1 }-> x :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   elem(z) -{ 0 }-> 0 :|: v0 >= 0, z = v0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> xs :|: z = 2, b >= 0, n >= 0, xs >= 0, z'' = n, z1 = m, ys >= 0, z' = b, z3 = ys, z2 = xs, m >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(m, xs) :|: n >= 0, xs >= 0, z'' = n, z = 1, z1 = m, ys >= 0, z' = 1, z3 = ys, z2 = xs, m >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(n, ys) :|: n >= 0, xs >= 0, z'' = n, z' = 2, z = 1, z1 = m, ys >= 0, z3 = ys, z2 = xs, m >= 0
   if(z, z', z'', z1, z2, z3) -{ 0 }-> 0 :|: z1 = v3, z3 = v5, v0 >= 0, v4 >= 0, z'' = v2, v1 >= 0, v5 >= 0, z = v0, z' = v1, z2 = v4, v2 >= 0, v3 >= 0
   isEmpty(z) -{ 1 }-> 2 :|: z = 0
   isEmpty(z) -{ 1 }-> 1 :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   isEmpty(z) -{ 0 }-> 0 :|: v0 >= 0, z = v0
   left(z) -{ 1 }-> l :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   left(z) -{ 1 }-> 0 :|: z = 0
   left(z) -{ 0 }-> 0 :|: v0 >= 0, z = v0
   listify(z, z') -{ 1 }-> if(isEmpty(n), isEmpty(left(n)), right(n), 1 + left(left(n)) + elem(left(n)) + (1 + right(left(n)) + elem(n) + right(n)), xs, append(xs, n)) :|: n >= 0, xs >= 0, z = n, z' = xs
   right(z) -{ 1 }-> r :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   right(z) -{ 1 }-> 0 :|: z = 0
   right(z) -{ 0 }-> 0 :|: v0 >= 0, z = v0
   toList(z) -{ 1 }-> listify(n, 0) :|: n >= 0, z = n

Only complete derivations are relevant for the runtime complexity.

----------------------------------------

(25) CompletionProof (UPPER BOUND(ID))
The transformation into a RNTS is sound, since:

(a) The obligation is a constructor system where every type has a constant constructor,

(b) The following defined symbols do not have to be completely defined, as they can never occur inside other defined symbols:

   listify_2
   if_6
   toList_1

(c) The following functions are completely defined:

   isEmpty_1
   left_1
   right_1
   elem_1
   append_2

Due to the following rules being added:

   isEmpty(v0) -> null_isEmpty [0]
   left(v0) -> null_left [0]
   right(v0) -> null_right [0]
   elem(v0) -> const [0]
   append(v0, v1) -> nil [0]

And the following fresh constants:    null_isEmpty, null_left, null_right, const

----------------------------------------

(26)
Obligation:
Runtime Complexity Weighted TRS where critical functions are completely defined. The underlying TRS is:

Runtime Complexity Weighted TRS with Types.
The TRS R consists of the following rules:

   isEmpty(empty) -> true [1]
   isEmpty(node(l, x, r)) -> false [1]
   left(empty) -> empty [1]
   left(node(l, x, r)) -> l [1]
   right(empty) -> empty [1]
   right(node(l, x, r)) -> r [1]
   elem(node(l, x, r)) -> x [1]
   append(nil, x) -> cons(x, nil) [1]
   append(cons(y, ys), x) -> cons(y, append(ys, x)) [1]
   listify(n, xs) -> if(isEmpty(n), isEmpty(left(n)), right(n), node(left(left(n)), elem(left(n)), node(right(left(n)), elem(n), right(n))), xs, append(xs, n)) [1]
   if(true, b, n, m, xs, ys) -> xs [1]
   if(false, false, n, m, xs, ys) -> listify(m, xs) [1]
   if(false, true, n, m, xs, ys) -> listify(n, ys) [1]
   toList(n) -> listify(n, nil) [1]
   isEmpty(v0) -> null_isEmpty [0]
   left(v0) -> null_left [0]
   right(v0) -> null_right [0]
   elem(v0) -> const [0]
   append(v0, v1) -> nil [0]

The TRS has the following type information:
isEmpty :: empty:node:y:null_left:null_right -> true:false:null_isEmpty
empty :: empty:node:y:null_left:null_right
true :: true:false:null_isEmpty
node :: empty:node:y:null_left:null_right -> const -> empty:node:y:null_left:null_right -> empty:node:y:null_left:null_right
false :: true:false:null_isEmpty
left :: empty:node:y:null_left:null_right -> empty:node:y:null_left:null_right
right :: empty:node:y:null_left:null_right -> empty:node:y:null_left:null_right
elem :: empty:node:y:null_left:null_right -> const
append :: nil:cons -> empty:node:y:null_left:null_right -> nil:cons
nil :: nil:cons
cons :: empty:node:y:null_left:null_right -> nil:cons -> nil:cons
y :: empty:node:y:null_left:null_right
listify :: empty:node:y:null_left:null_right -> nil:cons -> nil:cons
if :: true:false:null_isEmpty -> true:false:null_isEmpty -> empty:node:y:null_left:null_right -> empty:node:y:null_left:null_right -> nil:cons -> nil:cons -> nil:cons
toList :: empty:node:y:null_left:null_right -> nil:cons
null_isEmpty :: true:false:null_isEmpty
null_left :: empty:node:y:null_left:null_right
null_right :: empty:node:y:null_left:null_right
const :: const

Rewrite Strategy: INNERMOST
----------------------------------------

(27) NarrowingProof (BOTH BOUNDS(ID, ID))
Narrowed the inner basic terms of all right-hand sides by a single narrowing step.
----------------------------------------

(28)
Obligation:
Runtime Complexity Weighted TRS where critical functions are completely defined. The underlying TRS is:

Runtime Complexity Weighted TRS with Types.
The TRS R consists of the following rules:

   isEmpty(empty) -> true [1]
   isEmpty(node(l, x, r)) -> false [1]
   left(empty) -> empty [1]
   left(node(l, x, r)) -> l [1]
   right(empty) -> empty [1]
   right(node(l, x, r)) -> r [1]
   elem(node(l, x, r)) -> x [1]
   append(nil, x) -> cons(x, nil) [1]
   append(cons(y, ys), x) -> cons(y, append(ys, x)) [1]
   listify(n, xs) -> if(isEmpty(n), isEmpty(left(n)), right(n), node(left(left(n)), elem(left(n)), node(right(left(n)), elem(n), right(n))), xs, append(xs, n)) [1]
   if(true, b, n, m, xs, ys) -> xs [1]
   if(false, false, n, m, xs, ys) -> listify(m, xs) [1]
   if(false, true, n, m, xs, ys) -> listify(n, ys) [1]
   toList(n) -> listify(n, nil) [1]
   isEmpty(v0) -> null_isEmpty [0]
   left(v0) -> null_left [0]
   right(v0) -> null_right [0]
   elem(v0) -> const [0]
   append(v0, v1) -> nil [0]

The TRS has the following type information:
isEmpty :: empty:node:y:null_left:null_right -> true:false:null_isEmpty
empty :: empty:node:y:null_left:null_right
true :: true:false:null_isEmpty
node :: empty:node:y:null_left:null_right -> const -> empty:node:y:null_left:null_right -> empty:node:y:null_left:null_right
false :: true:false:null_isEmpty
left :: empty:node:y:null_left:null_right -> empty:node:y:null_left:null_right
right :: empty:node:y:null_left:null_right -> empty:node:y:null_left:null_right
elem :: empty:node:y:null_left:null_right -> const
append :: nil:cons -> empty:node:y:null_left:null_right -> nil:cons
nil :: nil:cons
cons :: empty:node:y:null_left:null_right -> nil:cons -> nil:cons
y :: empty:node:y:null_left:null_right
listify :: empty:node:y:null_left:null_right -> nil:cons -> nil:cons
if :: true:false:null_isEmpty -> true:false:null_isEmpty -> empty:node:y:null_left:null_right -> empty:node:y:null_left:null_right -> nil:cons -> nil:cons -> nil:cons
toList :: empty:node:y:null_left:null_right -> nil:cons
null_isEmpty :: true:false:null_isEmpty
null_left :: empty:node:y:null_left:null_right
null_right :: empty:node:y:null_left:null_right
const :: const

Rewrite Strategy: INNERMOST
----------------------------------------

(29) CpxTypedWeightedTrsToRntsProof (UPPER BOUND(ID))
Transformed the TRS into an over-approximating RNTS by (improved) Size Abstraction.
The constant constructors are abstracted as follows:

   empty => 0
   true => 2
   false => 1
   nil => 0
   y => 1
   null_isEmpty => 0
   null_left => 0
   null_right => 0
   const => 0

----------------------------------------

(30)
Obligation:
Complexity RNTS consisting of the following rules:

   append(z, z') -{ 0 }-> 0 :|: v0 >= 0, v1 >= 0, z = v0, z' = v1
   append(z, z') -{ 1 }-> 1 + x + 0 :|: z' = x, x >= 0, z = 0
   append(z, z') -{ 1 }-> 1 + 1 + append(ys, x) :|: z' = x, ys >= 0, x >= 0, z = 1 + 1 + ys
   elem(z) -{ 1 }-> x :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   elem(z) -{ 0 }-> 0 :|: v0 >= 0, z = v0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> xs :|: z = 2, b >= 0, n >= 0, xs >= 0, z'' = n, z1 = m, ys >= 0, z' = b, z3 = ys, z2 = xs, m >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(m, xs) :|: n >= 0, xs >= 0, z'' = n, z = 1, z1 = m, ys >= 0, z' = 1, z3 = ys, z2 = xs, m >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(n, ys) :|: n >= 0, xs >= 0, z'' = n, z' = 2, z = 1, z1 = m, ys >= 0, z3 = ys, z2 = xs, m >= 0
   isEmpty(z) -{ 1 }-> 2 :|: z = 0
   isEmpty(z) -{ 1 }-> 1 :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   isEmpty(z) -{ 0 }-> 0 :|: v0 >= 0, z = v0
   left(z) -{ 1 }-> l :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   left(z) -{ 1 }-> 0 :|: z = 0
   left(z) -{ 0 }-> 0 :|: v0 >= 0, z = v0
   listify(z, z') -{ 1 }-> if(isEmpty(n), isEmpty(left(n)), right(n), 1 + left(left(n)) + elem(left(n)) + (1 + right(left(n)) + elem(n) + right(n)), xs, append(xs, n)) :|: n >= 0, xs >= 0, z = n, z' = xs
   right(z) -{ 1 }-> r :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   right(z) -{ 1 }-> 0 :|: z = 0
   right(z) -{ 0 }-> 0 :|: v0 >= 0, z = v0
   toList(z) -{ 1 }-> listify(n, 0) :|: n >= 0, z = n


----------------------------------------

(31) InliningProof (UPPER BOUND(ID))
Inlined the following terminating rules on right-hand sides where appropriate:

   isEmpty(z) -{ 1 }-> 2 :|: z = 0
   isEmpty(z) -{ 0 }-> 0 :|: v0 >= 0, z = v0
   isEmpty(z) -{ 1 }-> 1 :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   right(z) -{ 1 }-> 0 :|: z = 0
   right(z) -{ 1 }-> r :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   right(z) -{ 0 }-> 0 :|: v0 >= 0, z = v0
   elem(z) -{ 1 }-> x :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   elem(z) -{ 0 }-> 0 :|: v0 >= 0, z = v0

----------------------------------------

(32)
Obligation:
Complexity RNTS consisting of the following rules:

   append(z, z') -{ 0 }-> 0 :|: v0 >= 0, v1 >= 0, z = v0, z' = v1
   append(z, z') -{ 1 }-> 1 + x + 0 :|: z' = x, x >= 0, z = 0
   append(z, z') -{ 1 }-> 1 + 1 + append(ys, x) :|: z' = x, ys >= 0, x >= 0, z = 1 + 1 + ys
   elem(z) -{ 1 }-> x :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   elem(z) -{ 0 }-> 0 :|: v0 >= 0, z = v0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> xs :|: z = 2, b >= 0, n >= 0, xs >= 0, z'' = n, z1 = m, ys >= 0, z' = b, z3 = ys, z2 = xs, m >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(m, xs) :|: n >= 0, xs >= 0, z'' = n, z = 1, z1 = m, ys >= 0, z' = 1, z3 = ys, z2 = xs, m >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(n, ys) :|: n >= 0, xs >= 0, z'' = n, z' = 2, z = 1, z1 = m, ys >= 0, z3 = ys, z2 = xs, m >= 0
   isEmpty(z) -{ 1 }-> 2 :|: z = 0
   isEmpty(z) -{ 1 }-> 1 :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   isEmpty(z) -{ 0 }-> 0 :|: v0 >= 0, z = v0
   left(z) -{ 1 }-> l :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   left(z) -{ 1 }-> 0 :|: z = 0
   left(z) -{ 0 }-> 0 :|: v0 >= 0, z = v0
   listify(z, z') -{ 4 }-> if(2, isEmpty(left(n)), 0, 1 + left(left(n)) + elem(left(n)) + (1 + right(left(n)) + 0 + 0), xs, append(xs, n)) :|: n >= 0, xs >= 0, z = n, z' = xs, n = 0, v0 >= 0, n = v0
   listify(z, z') -{ 3 }-> if(2, isEmpty(left(n)), 0, 1 + left(left(n)) + elem(left(n)) + (1 + right(left(n)) + 0 + 0), xs, append(xs, n)) :|: n >= 0, xs >= 0, z = n, z' = xs, n = 0, v0 >= 0, n = v0, v0' >= 0, n = v0'
   listify(z, z') -{ 2 }-> if(2, isEmpty(left(n)), 0, 1 + left(left(n)) + elem(left(n)) + (1 + right(left(n)) + 0 + 0), xs, append(xs, n)) :|: n >= 0, xs >= 0, z = n, z' = xs, n = 0, v0 >= 0, n = v0, v0' >= 0, n = v0', v0'' >= 0, n = v0''
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(n)), r', 1 + left(left(n)) + elem(left(n)) + (1 + right(left(n)) + x'' + 0), xs, append(xs, n)) :|: n >= 0, xs >= 0, z = n, z' = xs, r >= 0, x >= 0, l >= 0, n = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, n = 1 + l' + x' + r', v0 >= 0, n = v0, r'' >= 0, x'' >= 0, l'' >= 0, n = 1 + l'' + x'' + r''
   listify(z, z') -{ 5 }-> if(1, isEmpty(left(n)), r', 1 + left(left(n)) + elem(left(n)) + (1 + right(left(n)) + x1 + r''), xs, append(xs, n)) :|: n >= 0, xs >= 0, z = n, z' = xs, r >= 0, x >= 0, l >= 0, n = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, n = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, n = 1 + l'' + x'' + r'', r1 >= 0, x1 >= 0, l1 >= 0, n = 1 + l1 + x1 + r1
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(n)), r', 1 + left(left(n)) + elem(left(n)) + (1 + right(left(n)) + 0 + r''), xs, append(xs, n)) :|: n >= 0, xs >= 0, z = n, z' = xs, r >= 0, x >= 0, l >= 0, n = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, n = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, n = 1 + l'' + x'' + r'', v0 >= 0, n = v0
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(n)), r', 1 + left(left(n)) + elem(left(n)) + (1 + right(left(n)) + 0 + 0), xs, append(xs, n)) :|: n >= 0, xs >= 0, z = n, z' = xs, r >= 0, x >= 0, l >= 0, n = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, n = 1 + l' + x' + r', v0 >= 0, n = v0, v0' >= 0, n = v0'
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(n)), 0, 1 + left(left(n)) + elem(left(n)) + (1 + right(left(n)) + x' + 0), xs, append(xs, n)) :|: n >= 0, xs >= 0, z = n, z' = xs, r >= 0, x >= 0, l >= 0, n = 1 + l + x + r, v0 >= 0, n = v0, v0' >= 0, n = v0', r' >= 0, x' >= 0, l' >= 0, n = 1 + l' + x' + r'
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(n)), 0, 1 + left(left(n)) + elem(left(n)) + (1 + right(left(n)) + x'' + r'), xs, append(xs, n)) :|: n >= 0, xs >= 0, z = n, z' = xs, r >= 0, x >= 0, l >= 0, n = 1 + l + x + r, v0 >= 0, n = v0, r' >= 0, x' >= 0, l' >= 0, n = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, n = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(n)), 0, 1 + left(left(n)) + elem(left(n)) + (1 + right(left(n)) + 0 + r'), xs, append(xs, n)) :|: n >= 0, xs >= 0, z = n, z' = xs, r >= 0, x >= 0, l >= 0, n = 1 + l + x + r, v0 >= 0, n = v0, r' >= 0, x' >= 0, l' >= 0, n = 1 + l' + x' + r', v0' >= 0, n = v0'
   listify(z, z') -{ 2 }-> if(1, isEmpty(left(n)), 0, 1 + left(left(n)) + elem(left(n)) + (1 + right(left(n)) + 0 + 0), xs, append(xs, n)) :|: n >= 0, xs >= 0, z = n, z' = xs, r >= 0, x >= 0, l >= 0, n = 1 + l + x + r, v0 >= 0, n = v0, v0' >= 0, n = v0', v0'' >= 0, n = v0''
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(n)), r, 1 + left(left(n)) + elem(left(n)) + (1 + right(left(n)) + x' + 0), xs, append(xs, n)) :|: n >= 0, xs >= 0, z = n, z' = xs, v0 >= 0, n = v0, r >= 0, x >= 0, l >= 0, n = 1 + l + x + r, v0' >= 0, n = v0', r' >= 0, x' >= 0, l' >= 0, n = 1 + l' + x' + r'
   listify(z, z') -{ 4 }-> if(0, isEmpty(left(n)), r, 1 + left(left(n)) + elem(left(n)) + (1 + right(left(n)) + x'' + r'), xs, append(xs, n)) :|: n >= 0, xs >= 0, z = n, z' = xs, v0 >= 0, n = v0, r >= 0, x >= 0, l >= 0, n = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, n = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, n = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(n)), r, 1 + left(left(n)) + elem(left(n)) + (1 + right(left(n)) + 0 + r'), xs, append(xs, n)) :|: n >= 0, xs >= 0, z = n, z' = xs, v0 >= 0, n = v0, r >= 0, x >= 0, l >= 0, n = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, n = 1 + l' + x' + r', v0' >= 0, n = v0'
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(n)), r, 1 + left(left(n)) + elem(left(n)) + (1 + right(left(n)) + 0 + 0), xs, append(xs, n)) :|: n >= 0, xs >= 0, z = n, z' = xs, v0 >= 0, n = v0, r >= 0, x >= 0, l >= 0, n = 1 + l + x + r, v0' >= 0, n = v0', v0'' >= 0, n = v0''
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(n)), 0, 1 + left(left(n)) + elem(left(n)) + (1 + right(left(n)) + x + 0), xs, append(xs, n)) :|: n >= 0, xs >= 0, z = n, z' = xs, v0 >= 0, n = v0, v0' >= 0, n = v0', v0'' >= 0, n = v0'', r >= 0, x >= 0, l >= 0, n = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(n)), 0, 1 + left(left(n)) + elem(left(n)) + (1 + right(left(n)) + x' + r), xs, append(xs, n)) :|: n >= 0, xs >= 0, z = n, z' = xs, v0 >= 0, n = v0, v0' >= 0, n = v0', r >= 0, x >= 0, l >= 0, n = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, n = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(n)), 0, 1 + left(left(n)) + elem(left(n)) + (1 + right(left(n)) + 0 + r), xs, append(xs, n)) :|: n >= 0, xs >= 0, z = n, z' = xs, v0 >= 0, n = v0, v0' >= 0, n = v0', r >= 0, x >= 0, l >= 0, n = 1 + l + x + r, v0'' >= 0, n = v0''
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(n)), 0, 1 + left(left(n)) + elem(left(n)) + (1 + right(left(n)) + 0 + 0), xs, append(xs, n)) :|: n >= 0, xs >= 0, z = n, z' = xs, v0 >= 0, n = v0, n = 0, v0' >= 0, n = v0'
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(n)), 0, 1 + left(left(n)) + elem(left(n)) + (1 + right(left(n)) + 0 + 0), xs, append(xs, n)) :|: n >= 0, xs >= 0, z = n, z' = xs, v0 >= 0, n = v0, n = 0, v0' >= 0, n = v0', v0'' >= 0, n = v0''
   listify(z, z') -{ 1 }-> if(0, isEmpty(left(n)), 0, 1 + left(left(n)) + elem(left(n)) + (1 + right(left(n)) + 0 + 0), xs, append(xs, n)) :|: n >= 0, xs >= 0, z = n, z' = xs, v0 >= 0, n = v0, v0' >= 0, n = v0', v0'' >= 0, n = v0'', v01 >= 0, n = v01
   right(z) -{ 1 }-> r :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   right(z) -{ 1 }-> 0 :|: z = 0
   right(z) -{ 0 }-> 0 :|: v0 >= 0, z = v0
   toList(z) -{ 1 }-> listify(n, 0) :|: n >= 0, z = n


----------------------------------------

(33) SimplificationProof (BOTH BOUNDS(ID, ID))
Simplified the RNTS by moving equalities from the constraints into the right-hand sides.
----------------------------------------

(34)
Obligation:
Complexity RNTS consisting of the following rules:

   append(z, z') -{ 0 }-> 0 :|: z >= 0, z' >= 0
   append(z, z') -{ 1 }-> 1 + z' + 0 :|: z' >= 0, z = 0
   append(z, z') -{ 1 }-> 1 + 1 + append(z - 2, z') :|: z - 2 >= 0, z' >= 0
   elem(z) -{ 1 }-> x :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   elem(z) -{ 0 }-> 0 :|: z >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> z2 :|: z = 2, z' >= 0, z'' >= 0, z2 >= 0, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z'', z3) :|: z'' >= 0, z2 >= 0, z' = 2, z = 1, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z1, z2) :|: z'' >= 0, z2 >= 0, z = 1, z3 >= 0, z' = 1, z1 >= 0
   isEmpty(z) -{ 1 }-> 2 :|: z = 0
   isEmpty(z) -{ 1 }-> 1 :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   isEmpty(z) -{ 0 }-> 0 :|: z >= 0
   left(z) -{ 1 }-> l :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   left(z) -{ 1 }-> 0 :|: z = 0
   left(z) -{ 0 }-> 0 :|: z >= 0
   listify(z, z') -{ 4 }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 3 }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 2 }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 5 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x1 + r''), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r'', r1 >= 0, x1 >= 0, l1 >= 0, z = 1 + l1 + x1 + r1
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r''), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 4 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + r), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 1 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0
   right(z) -{ 1 }-> r :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   right(z) -{ 1 }-> 0 :|: z = 0
   right(z) -{ 0 }-> 0 :|: z >= 0
   toList(z) -{ 1 }-> listify(z, 0) :|: z >= 0


----------------------------------------

(35) CpxRntsAnalysisOrderProof (BOTH BOUNDS(ID, ID))
Found the following analysis order by SCC decomposition:

   { isEmpty }
   { elem }
   { append }
   { right }
   { left }
   { listify, if }
   { toList }

----------------------------------------

(36)
Obligation:
Complexity RNTS consisting of the following rules:

   append(z, z') -{ 0 }-> 0 :|: z >= 0, z' >= 0
   append(z, z') -{ 1 }-> 1 + z' + 0 :|: z' >= 0, z = 0
   append(z, z') -{ 1 }-> 1 + 1 + append(z - 2, z') :|: z - 2 >= 0, z' >= 0
   elem(z) -{ 1 }-> x :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   elem(z) -{ 0 }-> 0 :|: z >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> z2 :|: z = 2, z' >= 0, z'' >= 0, z2 >= 0, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z'', z3) :|: z'' >= 0, z2 >= 0, z' = 2, z = 1, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z1, z2) :|: z'' >= 0, z2 >= 0, z = 1, z3 >= 0, z' = 1, z1 >= 0
   isEmpty(z) -{ 1 }-> 2 :|: z = 0
   isEmpty(z) -{ 1 }-> 1 :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   isEmpty(z) -{ 0 }-> 0 :|: z >= 0
   left(z) -{ 1 }-> l :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   left(z) -{ 1 }-> 0 :|: z = 0
   left(z) -{ 0 }-> 0 :|: z >= 0
   listify(z, z') -{ 4 }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 3 }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 2 }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 5 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x1 + r''), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r'', r1 >= 0, x1 >= 0, l1 >= 0, z = 1 + l1 + x1 + r1
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r''), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 4 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + r), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 1 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0
   right(z) -{ 1 }-> r :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   right(z) -{ 1 }-> 0 :|: z = 0
   right(z) -{ 0 }-> 0 :|: z >= 0
   toList(z) -{ 1 }-> listify(z, 0) :|: z >= 0

Function symbols to be analyzed: {isEmpty}, {elem}, {append}, {right}, {left}, {listify,if}, {toList}

----------------------------------------

(37) ResultPropagationProof (UPPER BOUND(ID))
Applied inner abstraction using the recently inferred runtime/size bounds where possible.
----------------------------------------

(38)
Obligation:
Complexity RNTS consisting of the following rules:

   append(z, z') -{ 0 }-> 0 :|: z >= 0, z' >= 0
   append(z, z') -{ 1 }-> 1 + z' + 0 :|: z' >= 0, z = 0
   append(z, z') -{ 1 }-> 1 + 1 + append(z - 2, z') :|: z - 2 >= 0, z' >= 0
   elem(z) -{ 1 }-> x :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   elem(z) -{ 0 }-> 0 :|: z >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> z2 :|: z = 2, z' >= 0, z'' >= 0, z2 >= 0, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z'', z3) :|: z'' >= 0, z2 >= 0, z' = 2, z = 1, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z1, z2) :|: z'' >= 0, z2 >= 0, z = 1, z3 >= 0, z' = 1, z1 >= 0
   isEmpty(z) -{ 1 }-> 2 :|: z = 0
   isEmpty(z) -{ 1 }-> 1 :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   isEmpty(z) -{ 0 }-> 0 :|: z >= 0
   left(z) -{ 1 }-> l :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   left(z) -{ 1 }-> 0 :|: z = 0
   left(z) -{ 0 }-> 0 :|: z >= 0
   listify(z, z') -{ 4 }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 3 }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 2 }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 5 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x1 + r''), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r'', r1 >= 0, x1 >= 0, l1 >= 0, z = 1 + l1 + x1 + r1
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r''), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 4 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + r), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 1 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0
   right(z) -{ 1 }-> r :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   right(z) -{ 1 }-> 0 :|: z = 0
   right(z) -{ 0 }-> 0 :|: z >= 0
   toList(z) -{ 1 }-> listify(z, 0) :|: z >= 0

Function symbols to be analyzed: {isEmpty}, {elem}, {append}, {right}, {left}, {listify,if}, {toList}

----------------------------------------

(39) IntTrsBoundProof (UPPER BOUND(ID))

Computed SIZE bound using CoFloCo for: isEmpty
after applying outer abstraction to obtain an ITS,
resulting in: O(1) with polynomial bound: 2

----------------------------------------

(40)
Obligation:
Complexity RNTS consisting of the following rules:

   append(z, z') -{ 0 }-> 0 :|: z >= 0, z' >= 0
   append(z, z') -{ 1 }-> 1 + z' + 0 :|: z' >= 0, z = 0
   append(z, z') -{ 1 }-> 1 + 1 + append(z - 2, z') :|: z - 2 >= 0, z' >= 0
   elem(z) -{ 1 }-> x :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   elem(z) -{ 0 }-> 0 :|: z >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> z2 :|: z = 2, z' >= 0, z'' >= 0, z2 >= 0, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z'', z3) :|: z'' >= 0, z2 >= 0, z' = 2, z = 1, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z1, z2) :|: z'' >= 0, z2 >= 0, z = 1, z3 >= 0, z' = 1, z1 >= 0
   isEmpty(z) -{ 1 }-> 2 :|: z = 0
   isEmpty(z) -{ 1 }-> 1 :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   isEmpty(z) -{ 0 }-> 0 :|: z >= 0
   left(z) -{ 1 }-> l :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   left(z) -{ 1 }-> 0 :|: z = 0
   left(z) -{ 0 }-> 0 :|: z >= 0
   listify(z, z') -{ 4 }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 3 }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 2 }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 5 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x1 + r''), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r'', r1 >= 0, x1 >= 0, l1 >= 0, z = 1 + l1 + x1 + r1
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r''), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 4 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + r), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 1 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0
   right(z) -{ 1 }-> r :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   right(z) -{ 1 }-> 0 :|: z = 0
   right(z) -{ 0 }-> 0 :|: z >= 0
   toList(z) -{ 1 }-> listify(z, 0) :|: z >= 0

Function symbols to be analyzed: {isEmpty}, {elem}, {append}, {right}, {left}, {listify,if}, {toList}
Previous analysis results are:
  isEmpty: runtime: ?, size: O(1) [2]

----------------------------------------

(41) IntTrsBoundProof (UPPER BOUND(ID))

Computed RUNTIME bound using CoFloCo for: isEmpty
after applying outer abstraction to obtain an ITS,
resulting in: O(1) with polynomial bound: 1

----------------------------------------

(42)
Obligation:
Complexity RNTS consisting of the following rules:

   append(z, z') -{ 0 }-> 0 :|: z >= 0, z' >= 0
   append(z, z') -{ 1 }-> 1 + z' + 0 :|: z' >= 0, z = 0
   append(z, z') -{ 1 }-> 1 + 1 + append(z - 2, z') :|: z - 2 >= 0, z' >= 0
   elem(z) -{ 1 }-> x :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   elem(z) -{ 0 }-> 0 :|: z >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> z2 :|: z = 2, z' >= 0, z'' >= 0, z2 >= 0, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z'', z3) :|: z'' >= 0, z2 >= 0, z' = 2, z = 1, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z1, z2) :|: z'' >= 0, z2 >= 0, z = 1, z3 >= 0, z' = 1, z1 >= 0
   isEmpty(z) -{ 1 }-> 2 :|: z = 0
   isEmpty(z) -{ 1 }-> 1 :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   isEmpty(z) -{ 0 }-> 0 :|: z >= 0
   left(z) -{ 1 }-> l :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   left(z) -{ 1 }-> 0 :|: z = 0
   left(z) -{ 0 }-> 0 :|: z >= 0
   listify(z, z') -{ 4 }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 3 }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 2 }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 5 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x1 + r''), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r'', r1 >= 0, x1 >= 0, l1 >= 0, z = 1 + l1 + x1 + r1
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r''), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 4 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + r), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 1 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0
   right(z) -{ 1 }-> r :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   right(z) -{ 1 }-> 0 :|: z = 0
   right(z) -{ 0 }-> 0 :|: z >= 0
   toList(z) -{ 1 }-> listify(z, 0) :|: z >= 0

Function symbols to be analyzed: {elem}, {append}, {right}, {left}, {listify,if}, {toList}
Previous analysis results are:
  isEmpty: runtime: O(1) [1], size: O(1) [2]

----------------------------------------

(43) ResultPropagationProof (UPPER BOUND(ID))
Applied inner abstraction using the recently inferred runtime/size bounds where possible.
----------------------------------------

(44)
Obligation:
Complexity RNTS consisting of the following rules:

   append(z, z') -{ 0 }-> 0 :|: z >= 0, z' >= 0
   append(z, z') -{ 1 }-> 1 + z' + 0 :|: z' >= 0, z = 0
   append(z, z') -{ 1 }-> 1 + 1 + append(z - 2, z') :|: z - 2 >= 0, z' >= 0
   elem(z) -{ 1 }-> x :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   elem(z) -{ 0 }-> 0 :|: z >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> z2 :|: z = 2, z' >= 0, z'' >= 0, z2 >= 0, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z'', z3) :|: z'' >= 0, z2 >= 0, z' = 2, z = 1, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z1, z2) :|: z'' >= 0, z2 >= 0, z = 1, z3 >= 0, z' = 1, z1 >= 0
   isEmpty(z) -{ 1 }-> 2 :|: z = 0
   isEmpty(z) -{ 1 }-> 1 :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   isEmpty(z) -{ 0 }-> 0 :|: z >= 0
   left(z) -{ 1 }-> l :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   left(z) -{ 1 }-> 0 :|: z = 0
   left(z) -{ 0 }-> 0 :|: z >= 0
   listify(z, z') -{ 4 }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 3 }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 2 }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 5 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x1 + r''), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r'', r1 >= 0, x1 >= 0, l1 >= 0, z = 1 + l1 + x1 + r1
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r''), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 4 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + r), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 1 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0
   right(z) -{ 1 }-> r :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   right(z) -{ 1 }-> 0 :|: z = 0
   right(z) -{ 0 }-> 0 :|: z >= 0
   toList(z) -{ 1 }-> listify(z, 0) :|: z >= 0

Function symbols to be analyzed: {elem}, {append}, {right}, {left}, {listify,if}, {toList}
Previous analysis results are:
  isEmpty: runtime: O(1) [1], size: O(1) [2]

----------------------------------------

(45) IntTrsBoundProof (UPPER BOUND(ID))

Computed SIZE bound using KoAT for: elem
after applying outer abstraction to obtain an ITS,
resulting in: O(n^1) with polynomial bound: z

----------------------------------------

(46)
Obligation:
Complexity RNTS consisting of the following rules:

   append(z, z') -{ 0 }-> 0 :|: z >= 0, z' >= 0
   append(z, z') -{ 1 }-> 1 + z' + 0 :|: z' >= 0, z = 0
   append(z, z') -{ 1 }-> 1 + 1 + append(z - 2, z') :|: z - 2 >= 0, z' >= 0
   elem(z) -{ 1 }-> x :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   elem(z) -{ 0 }-> 0 :|: z >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> z2 :|: z = 2, z' >= 0, z'' >= 0, z2 >= 0, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z'', z3) :|: z'' >= 0, z2 >= 0, z' = 2, z = 1, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z1, z2) :|: z'' >= 0, z2 >= 0, z = 1, z3 >= 0, z' = 1, z1 >= 0
   isEmpty(z) -{ 1 }-> 2 :|: z = 0
   isEmpty(z) -{ 1 }-> 1 :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   isEmpty(z) -{ 0 }-> 0 :|: z >= 0
   left(z) -{ 1 }-> l :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   left(z) -{ 1 }-> 0 :|: z = 0
   left(z) -{ 0 }-> 0 :|: z >= 0
   listify(z, z') -{ 4 }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 3 }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 2 }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 5 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x1 + r''), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r'', r1 >= 0, x1 >= 0, l1 >= 0, z = 1 + l1 + x1 + r1
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r''), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 4 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + r), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 1 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0
   right(z) -{ 1 }-> r :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   right(z) -{ 1 }-> 0 :|: z = 0
   right(z) -{ 0 }-> 0 :|: z >= 0
   toList(z) -{ 1 }-> listify(z, 0) :|: z >= 0

Function symbols to be analyzed: {elem}, {append}, {right}, {left}, {listify,if}, {toList}
Previous analysis results are:
  isEmpty: runtime: O(1) [1], size: O(1) [2]
  elem: runtime: ?, size: O(n^1) [z]

----------------------------------------

(47) IntTrsBoundProof (UPPER BOUND(ID))

Computed RUNTIME bound using CoFloCo for: elem
after applying outer abstraction to obtain an ITS,
resulting in: O(1) with polynomial bound: 1

----------------------------------------

(48)
Obligation:
Complexity RNTS consisting of the following rules:

   append(z, z') -{ 0 }-> 0 :|: z >= 0, z' >= 0
   append(z, z') -{ 1 }-> 1 + z' + 0 :|: z' >= 0, z = 0
   append(z, z') -{ 1 }-> 1 + 1 + append(z - 2, z') :|: z - 2 >= 0, z' >= 0
   elem(z) -{ 1 }-> x :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   elem(z) -{ 0 }-> 0 :|: z >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> z2 :|: z = 2, z' >= 0, z'' >= 0, z2 >= 0, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z'', z3) :|: z'' >= 0, z2 >= 0, z' = 2, z = 1, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z1, z2) :|: z'' >= 0, z2 >= 0, z = 1, z3 >= 0, z' = 1, z1 >= 0
   isEmpty(z) -{ 1 }-> 2 :|: z = 0
   isEmpty(z) -{ 1 }-> 1 :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   isEmpty(z) -{ 0 }-> 0 :|: z >= 0
   left(z) -{ 1 }-> l :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   left(z) -{ 1 }-> 0 :|: z = 0
   left(z) -{ 0 }-> 0 :|: z >= 0
   listify(z, z') -{ 4 }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 3 }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 2 }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 5 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x1 + r''), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r'', r1 >= 0, x1 >= 0, l1 >= 0, z = 1 + l1 + x1 + r1
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r''), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 4 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + r), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 1 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0
   right(z) -{ 1 }-> r :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   right(z) -{ 1 }-> 0 :|: z = 0
   right(z) -{ 0 }-> 0 :|: z >= 0
   toList(z) -{ 1 }-> listify(z, 0) :|: z >= 0

Function symbols to be analyzed: {append}, {right}, {left}, {listify,if}, {toList}
Previous analysis results are:
  isEmpty: runtime: O(1) [1], size: O(1) [2]
  elem: runtime: O(1) [1], size: O(n^1) [z]

----------------------------------------

(49) ResultPropagationProof (UPPER BOUND(ID))
Applied inner abstraction using the recently inferred runtime/size bounds where possible.
----------------------------------------

(50)
Obligation:
Complexity RNTS consisting of the following rules:

   append(z, z') -{ 0 }-> 0 :|: z >= 0, z' >= 0
   append(z, z') -{ 1 }-> 1 + z' + 0 :|: z' >= 0, z = 0
   append(z, z') -{ 1 }-> 1 + 1 + append(z - 2, z') :|: z - 2 >= 0, z' >= 0
   elem(z) -{ 1 }-> x :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   elem(z) -{ 0 }-> 0 :|: z >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> z2 :|: z = 2, z' >= 0, z'' >= 0, z2 >= 0, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z'', z3) :|: z'' >= 0, z2 >= 0, z' = 2, z = 1, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z1, z2) :|: z'' >= 0, z2 >= 0, z = 1, z3 >= 0, z' = 1, z1 >= 0
   isEmpty(z) -{ 1 }-> 2 :|: z = 0
   isEmpty(z) -{ 1 }-> 1 :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   isEmpty(z) -{ 0 }-> 0 :|: z >= 0
   left(z) -{ 1 }-> l :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   left(z) -{ 1 }-> 0 :|: z = 0
   left(z) -{ 0 }-> 0 :|: z >= 0
   listify(z, z') -{ 4 }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 3 }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 2 }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 5 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x1 + r''), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r'', r1 >= 0, x1 >= 0, l1 >= 0, z = 1 + l1 + x1 + r1
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r''), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 4 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + r), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 1 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0
   right(z) -{ 1 }-> r :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   right(z) -{ 1 }-> 0 :|: z = 0
   right(z) -{ 0 }-> 0 :|: z >= 0
   toList(z) -{ 1 }-> listify(z, 0) :|: z >= 0

Function symbols to be analyzed: {append}, {right}, {left}, {listify,if}, {toList}
Previous analysis results are:
  isEmpty: runtime: O(1) [1], size: O(1) [2]
  elem: runtime: O(1) [1], size: O(n^1) [z]

----------------------------------------

(51) IntTrsBoundProof (UPPER BOUND(ID))

Computed SIZE bound using CoFloCo for: append
after applying outer abstraction to obtain an ITS,
resulting in: O(n^1) with polynomial bound: 1 + z + z'

----------------------------------------

(52)
Obligation:
Complexity RNTS consisting of the following rules:

   append(z, z') -{ 0 }-> 0 :|: z >= 0, z' >= 0
   append(z, z') -{ 1 }-> 1 + z' + 0 :|: z' >= 0, z = 0
   append(z, z') -{ 1 }-> 1 + 1 + append(z - 2, z') :|: z - 2 >= 0, z' >= 0
   elem(z) -{ 1 }-> x :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   elem(z) -{ 0 }-> 0 :|: z >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> z2 :|: z = 2, z' >= 0, z'' >= 0, z2 >= 0, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z'', z3) :|: z'' >= 0, z2 >= 0, z' = 2, z = 1, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z1, z2) :|: z'' >= 0, z2 >= 0, z = 1, z3 >= 0, z' = 1, z1 >= 0
   isEmpty(z) -{ 1 }-> 2 :|: z = 0
   isEmpty(z) -{ 1 }-> 1 :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   isEmpty(z) -{ 0 }-> 0 :|: z >= 0
   left(z) -{ 1 }-> l :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   left(z) -{ 1 }-> 0 :|: z = 0
   left(z) -{ 0 }-> 0 :|: z >= 0
   listify(z, z') -{ 4 }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 3 }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 2 }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 5 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x1 + r''), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r'', r1 >= 0, x1 >= 0, l1 >= 0, z = 1 + l1 + x1 + r1
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r''), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 4 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + r), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 1 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0
   right(z) -{ 1 }-> r :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   right(z) -{ 1 }-> 0 :|: z = 0
   right(z) -{ 0 }-> 0 :|: z >= 0
   toList(z) -{ 1 }-> listify(z, 0) :|: z >= 0

Function symbols to be analyzed: {append}, {right}, {left}, {listify,if}, {toList}
Previous analysis results are:
  isEmpty: runtime: O(1) [1], size: O(1) [2]
  elem: runtime: O(1) [1], size: O(n^1) [z]
  append: runtime: ?, size: O(n^1) [1 + z + z']

----------------------------------------

(53) IntTrsBoundProof (UPPER BOUND(ID))

Computed RUNTIME bound using KoAT for: append
after applying outer abstraction to obtain an ITS,
resulting in: O(n^1) with polynomial bound: 1 + z

----------------------------------------

(54)
Obligation:
Complexity RNTS consisting of the following rules:

   append(z, z') -{ 0 }-> 0 :|: z >= 0, z' >= 0
   append(z, z') -{ 1 }-> 1 + z' + 0 :|: z' >= 0, z = 0
   append(z, z') -{ 1 }-> 1 + 1 + append(z - 2, z') :|: z - 2 >= 0, z' >= 0
   elem(z) -{ 1 }-> x :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   elem(z) -{ 0 }-> 0 :|: z >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> z2 :|: z = 2, z' >= 0, z'' >= 0, z2 >= 0, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z'', z3) :|: z'' >= 0, z2 >= 0, z' = 2, z = 1, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z1, z2) :|: z'' >= 0, z2 >= 0, z = 1, z3 >= 0, z' = 1, z1 >= 0
   isEmpty(z) -{ 1 }-> 2 :|: z = 0
   isEmpty(z) -{ 1 }-> 1 :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   isEmpty(z) -{ 0 }-> 0 :|: z >= 0
   left(z) -{ 1 }-> l :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   left(z) -{ 1 }-> 0 :|: z = 0
   left(z) -{ 0 }-> 0 :|: z >= 0
   listify(z, z') -{ 4 }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 3 }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 2 }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 5 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x1 + r''), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r'', r1 >= 0, x1 >= 0, l1 >= 0, z = 1 + l1 + x1 + r1
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r''), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 4 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 4 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x + 0), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + r), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r), z', append(z', z)) :|: z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 2 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 1 }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', append(z', z)) :|: z >= 0, z' >= 0
   right(z) -{ 1 }-> r :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   right(z) -{ 1 }-> 0 :|: z = 0
   right(z) -{ 0 }-> 0 :|: z >= 0
   toList(z) -{ 1 }-> listify(z, 0) :|: z >= 0

Function symbols to be analyzed: {right}, {left}, {listify,if}, {toList}
Previous analysis results are:
  isEmpty: runtime: O(1) [1], size: O(1) [2]
  elem: runtime: O(1) [1], size: O(n^1) [z]
  append: runtime: O(n^1) [1 + z], size: O(n^1) [1 + z + z']

----------------------------------------

(55) ResultPropagationProof (UPPER BOUND(ID))
Applied inner abstraction using the recently inferred runtime/size bounds where possible.
----------------------------------------

(56)
Obligation:
Complexity RNTS consisting of the following rules:

   append(z, z') -{ 0 }-> 0 :|: z >= 0, z' >= 0
   append(z, z') -{ 1 }-> 1 + z' + 0 :|: z' >= 0, z = 0
   append(z, z') -{ z }-> 1 + 1 + s :|: s >= 0, s <= z - 2 + z' + 1, z - 2 >= 0, z' >= 0
   elem(z) -{ 1 }-> x :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   elem(z) -{ 0 }-> 0 :|: z >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> z2 :|: z = 2, z' >= 0, z'' >= 0, z2 >= 0, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z'', z3) :|: z'' >= 0, z2 >= 0, z' = 2, z = 1, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z1, z2) :|: z'' >= 0, z2 >= 0, z = 1, z3 >= 0, z' = 1, z1 >= 0
   isEmpty(z) -{ 1 }-> 2 :|: z = 0
   isEmpty(z) -{ 1 }-> 1 :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   isEmpty(z) -{ 0 }-> 0 :|: z >= 0
   left(z) -{ 1 }-> l :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   left(z) -{ 1 }-> 0 :|: z = 0
   left(z) -{ 0 }-> 0 :|: z >= 0
   listify(z, z') -{ 5 + z' }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s') :|: s' >= 0, s' <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 4 + z' }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s'') :|: s'' >= 0, s'' <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 3 + z' }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s1) :|: s1 >= 0, s1 <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 5 + z' }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + 0), z', s14) :|: s14 >= 0, s14 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 6 + z' }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x1 + r''), z', s12) :|: s12 >= 0, s12 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r'', r1 >= 0, x1 >= 0, l1 >= 0, z = 1 + l1 + x1 + r1
   listify(z, z') -{ 5 + z' }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r''), z', s13) :|: s13 >= 0, s13 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 4 + z' }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s15) :|: s15 >= 0, s15 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 4 + z' }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', s18) :|: s18 >= 0, s18 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 5 + z' }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', s16) :|: s16 >= 0, s16 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 4 + z' }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', s17) :|: s17 >= 0, s17 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 3 + z' }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s19) :|: s19 >= 0, s19 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 4 + z' }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', s6) :|: s6 >= 0, s6 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 5 + z' }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', s4) :|: s4 >= 0, s4 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 4 + z' }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', s5) :|: s5 >= 0, s5 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 3 + z' }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s7) :|: s7 >= 0, s7 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x + 0), z', s10) :|: s10 >= 0, s10 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 4 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + r), z', s8) :|: s8 >= 0, s8 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 3 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r), z', s9) :|: s9 >= 0, s9 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 2 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s11) :|: s11 >= 0, s11 <= z' + z + 1, z >= 0, z' >= 0
   listify(z, z') -{ 4 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s2) :|: s2 >= 0, s2 <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 3 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s3) :|: s3 >= 0, s3 <= z' + z + 1, z >= 0, z' >= 0, z = 0
   right(z) -{ 1 }-> r :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   right(z) -{ 1 }-> 0 :|: z = 0
   right(z) -{ 0 }-> 0 :|: z >= 0
   toList(z) -{ 1 }-> listify(z, 0) :|: z >= 0

Function symbols to be analyzed: {right}, {left}, {listify,if}, {toList}
Previous analysis results are:
  isEmpty: runtime: O(1) [1], size: O(1) [2]
  elem: runtime: O(1) [1], size: O(n^1) [z]
  append: runtime: O(n^1) [1 + z], size: O(n^1) [1 + z + z']

----------------------------------------

(57) IntTrsBoundProof (UPPER BOUND(ID))

Computed SIZE bound using KoAT for: right
after applying outer abstraction to obtain an ITS,
resulting in: O(n^1) with polynomial bound: z

----------------------------------------

(58)
Obligation:
Complexity RNTS consisting of the following rules:

   append(z, z') -{ 0 }-> 0 :|: z >= 0, z' >= 0
   append(z, z') -{ 1 }-> 1 + z' + 0 :|: z' >= 0, z = 0
   append(z, z') -{ z }-> 1 + 1 + s :|: s >= 0, s <= z - 2 + z' + 1, z - 2 >= 0, z' >= 0
   elem(z) -{ 1 }-> x :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   elem(z) -{ 0 }-> 0 :|: z >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> z2 :|: z = 2, z' >= 0, z'' >= 0, z2 >= 0, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z'', z3) :|: z'' >= 0, z2 >= 0, z' = 2, z = 1, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z1, z2) :|: z'' >= 0, z2 >= 0, z = 1, z3 >= 0, z' = 1, z1 >= 0
   isEmpty(z) -{ 1 }-> 2 :|: z = 0
   isEmpty(z) -{ 1 }-> 1 :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   isEmpty(z) -{ 0 }-> 0 :|: z >= 0
   left(z) -{ 1 }-> l :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   left(z) -{ 1 }-> 0 :|: z = 0
   left(z) -{ 0 }-> 0 :|: z >= 0
   listify(z, z') -{ 5 + z' }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s') :|: s' >= 0, s' <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 4 + z' }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s'') :|: s'' >= 0, s'' <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 3 + z' }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s1) :|: s1 >= 0, s1 <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 5 + z' }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + 0), z', s14) :|: s14 >= 0, s14 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 6 + z' }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x1 + r''), z', s12) :|: s12 >= 0, s12 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r'', r1 >= 0, x1 >= 0, l1 >= 0, z = 1 + l1 + x1 + r1
   listify(z, z') -{ 5 + z' }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r''), z', s13) :|: s13 >= 0, s13 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 4 + z' }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s15) :|: s15 >= 0, s15 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 4 + z' }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', s18) :|: s18 >= 0, s18 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 5 + z' }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', s16) :|: s16 >= 0, s16 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 4 + z' }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', s17) :|: s17 >= 0, s17 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 3 + z' }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s19) :|: s19 >= 0, s19 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 4 + z' }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', s6) :|: s6 >= 0, s6 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 5 + z' }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', s4) :|: s4 >= 0, s4 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 4 + z' }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', s5) :|: s5 >= 0, s5 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 3 + z' }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s7) :|: s7 >= 0, s7 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x + 0), z', s10) :|: s10 >= 0, s10 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 4 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + r), z', s8) :|: s8 >= 0, s8 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 3 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r), z', s9) :|: s9 >= 0, s9 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 2 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s11) :|: s11 >= 0, s11 <= z' + z + 1, z >= 0, z' >= 0
   listify(z, z') -{ 4 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s2) :|: s2 >= 0, s2 <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 3 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s3) :|: s3 >= 0, s3 <= z' + z + 1, z >= 0, z' >= 0, z = 0
   right(z) -{ 1 }-> r :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   right(z) -{ 1 }-> 0 :|: z = 0
   right(z) -{ 0 }-> 0 :|: z >= 0
   toList(z) -{ 1 }-> listify(z, 0) :|: z >= 0

Function symbols to be analyzed: {right}, {left}, {listify,if}, {toList}
Previous analysis results are:
  isEmpty: runtime: O(1) [1], size: O(1) [2]
  elem: runtime: O(1) [1], size: O(n^1) [z]
  append: runtime: O(n^1) [1 + z], size: O(n^1) [1 + z + z']
  right: runtime: ?, size: O(n^1) [z]

----------------------------------------

(59) IntTrsBoundProof (UPPER BOUND(ID))

Computed RUNTIME bound using CoFloCo for: right
after applying outer abstraction to obtain an ITS,
resulting in: O(1) with polynomial bound: 1

----------------------------------------

(60)
Obligation:
Complexity RNTS consisting of the following rules:

   append(z, z') -{ 0 }-> 0 :|: z >= 0, z' >= 0
   append(z, z') -{ 1 }-> 1 + z' + 0 :|: z' >= 0, z = 0
   append(z, z') -{ z }-> 1 + 1 + s :|: s >= 0, s <= z - 2 + z' + 1, z - 2 >= 0, z' >= 0
   elem(z) -{ 1 }-> x :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   elem(z) -{ 0 }-> 0 :|: z >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> z2 :|: z = 2, z' >= 0, z'' >= 0, z2 >= 0, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z'', z3) :|: z'' >= 0, z2 >= 0, z' = 2, z = 1, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z1, z2) :|: z'' >= 0, z2 >= 0, z = 1, z3 >= 0, z' = 1, z1 >= 0
   isEmpty(z) -{ 1 }-> 2 :|: z = 0
   isEmpty(z) -{ 1 }-> 1 :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   isEmpty(z) -{ 0 }-> 0 :|: z >= 0
   left(z) -{ 1 }-> l :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   left(z) -{ 1 }-> 0 :|: z = 0
   left(z) -{ 0 }-> 0 :|: z >= 0
   listify(z, z') -{ 5 + z' }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s') :|: s' >= 0, s' <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 4 + z' }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s'') :|: s'' >= 0, s'' <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 3 + z' }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s1) :|: s1 >= 0, s1 <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 5 + z' }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + 0), z', s14) :|: s14 >= 0, s14 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 6 + z' }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x1 + r''), z', s12) :|: s12 >= 0, s12 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r'', r1 >= 0, x1 >= 0, l1 >= 0, z = 1 + l1 + x1 + r1
   listify(z, z') -{ 5 + z' }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r''), z', s13) :|: s13 >= 0, s13 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 4 + z' }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s15) :|: s15 >= 0, s15 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 4 + z' }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', s18) :|: s18 >= 0, s18 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 5 + z' }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', s16) :|: s16 >= 0, s16 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 4 + z' }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', s17) :|: s17 >= 0, s17 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 3 + z' }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s19) :|: s19 >= 0, s19 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 4 + z' }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', s6) :|: s6 >= 0, s6 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 5 + z' }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', s4) :|: s4 >= 0, s4 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 4 + z' }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', s5) :|: s5 >= 0, s5 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 3 + z' }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s7) :|: s7 >= 0, s7 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x + 0), z', s10) :|: s10 >= 0, s10 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 4 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + r), z', s8) :|: s8 >= 0, s8 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 3 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r), z', s9) :|: s9 >= 0, s9 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 2 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s11) :|: s11 >= 0, s11 <= z' + z + 1, z >= 0, z' >= 0
   listify(z, z') -{ 4 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s2) :|: s2 >= 0, s2 <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 3 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s3) :|: s3 >= 0, s3 <= z' + z + 1, z >= 0, z' >= 0, z = 0
   right(z) -{ 1 }-> r :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   right(z) -{ 1 }-> 0 :|: z = 0
   right(z) -{ 0 }-> 0 :|: z >= 0
   toList(z) -{ 1 }-> listify(z, 0) :|: z >= 0

Function symbols to be analyzed: {left}, {listify,if}, {toList}
Previous analysis results are:
  isEmpty: runtime: O(1) [1], size: O(1) [2]
  elem: runtime: O(1) [1], size: O(n^1) [z]
  append: runtime: O(n^1) [1 + z], size: O(n^1) [1 + z + z']
  right: runtime: O(1) [1], size: O(n^1) [z]

----------------------------------------

(61) ResultPropagationProof (UPPER BOUND(ID))
Applied inner abstraction using the recently inferred runtime/size bounds where possible.
----------------------------------------

(62)
Obligation:
Complexity RNTS consisting of the following rules:

   append(z, z') -{ 0 }-> 0 :|: z >= 0, z' >= 0
   append(z, z') -{ 1 }-> 1 + z' + 0 :|: z' >= 0, z = 0
   append(z, z') -{ z }-> 1 + 1 + s :|: s >= 0, s <= z - 2 + z' + 1, z - 2 >= 0, z' >= 0
   elem(z) -{ 1 }-> x :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   elem(z) -{ 0 }-> 0 :|: z >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> z2 :|: z = 2, z' >= 0, z'' >= 0, z2 >= 0, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z'', z3) :|: z'' >= 0, z2 >= 0, z' = 2, z = 1, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z1, z2) :|: z'' >= 0, z2 >= 0, z = 1, z3 >= 0, z' = 1, z1 >= 0
   isEmpty(z) -{ 1 }-> 2 :|: z = 0
   isEmpty(z) -{ 1 }-> 1 :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   isEmpty(z) -{ 0 }-> 0 :|: z >= 0
   left(z) -{ 1 }-> l :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   left(z) -{ 1 }-> 0 :|: z = 0
   left(z) -{ 0 }-> 0 :|: z >= 0
   listify(z, z') -{ 5 + z' }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s') :|: s' >= 0, s' <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 4 + z' }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s'') :|: s'' >= 0, s'' <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 3 + z' }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s1) :|: s1 >= 0, s1 <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 5 + z' }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + 0), z', s14) :|: s14 >= 0, s14 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 6 + z' }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x1 + r''), z', s12) :|: s12 >= 0, s12 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r'', r1 >= 0, x1 >= 0, l1 >= 0, z = 1 + l1 + x1 + r1
   listify(z, z') -{ 5 + z' }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r''), z', s13) :|: s13 >= 0, s13 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 4 + z' }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s15) :|: s15 >= 0, s15 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 4 + z' }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', s18) :|: s18 >= 0, s18 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 5 + z' }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', s16) :|: s16 >= 0, s16 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 4 + z' }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', s17) :|: s17 >= 0, s17 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 3 + z' }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s19) :|: s19 >= 0, s19 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 4 + z' }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', s6) :|: s6 >= 0, s6 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 5 + z' }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', s4) :|: s4 >= 0, s4 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 4 + z' }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', s5) :|: s5 >= 0, s5 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 3 + z' }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s7) :|: s7 >= 0, s7 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x + 0), z', s10) :|: s10 >= 0, s10 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 4 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + r), z', s8) :|: s8 >= 0, s8 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 3 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r), z', s9) :|: s9 >= 0, s9 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 2 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s11) :|: s11 >= 0, s11 <= z' + z + 1, z >= 0, z' >= 0
   listify(z, z') -{ 4 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s2) :|: s2 >= 0, s2 <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 3 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s3) :|: s3 >= 0, s3 <= z' + z + 1, z >= 0, z' >= 0, z = 0
   right(z) -{ 1 }-> r :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   right(z) -{ 1 }-> 0 :|: z = 0
   right(z) -{ 0 }-> 0 :|: z >= 0
   toList(z) -{ 1 }-> listify(z, 0) :|: z >= 0

Function symbols to be analyzed: {left}, {listify,if}, {toList}
Previous analysis results are:
  isEmpty: runtime: O(1) [1], size: O(1) [2]
  elem: runtime: O(1) [1], size: O(n^1) [z]
  append: runtime: O(n^1) [1 + z], size: O(n^1) [1 + z + z']
  right: runtime: O(1) [1], size: O(n^1) [z]

----------------------------------------

(63) IntTrsBoundProof (UPPER BOUND(ID))

Computed SIZE bound using KoAT for: left
after applying outer abstraction to obtain an ITS,
resulting in: O(n^1) with polynomial bound: z

----------------------------------------

(64)
Obligation:
Complexity RNTS consisting of the following rules:

   append(z, z') -{ 0 }-> 0 :|: z >= 0, z' >= 0
   append(z, z') -{ 1 }-> 1 + z' + 0 :|: z' >= 0, z = 0
   append(z, z') -{ z }-> 1 + 1 + s :|: s >= 0, s <= z - 2 + z' + 1, z - 2 >= 0, z' >= 0
   elem(z) -{ 1 }-> x :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   elem(z) -{ 0 }-> 0 :|: z >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> z2 :|: z = 2, z' >= 0, z'' >= 0, z2 >= 0, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z'', z3) :|: z'' >= 0, z2 >= 0, z' = 2, z = 1, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z1, z2) :|: z'' >= 0, z2 >= 0, z = 1, z3 >= 0, z' = 1, z1 >= 0
   isEmpty(z) -{ 1 }-> 2 :|: z = 0
   isEmpty(z) -{ 1 }-> 1 :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   isEmpty(z) -{ 0 }-> 0 :|: z >= 0
   left(z) -{ 1 }-> l :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   left(z) -{ 1 }-> 0 :|: z = 0
   left(z) -{ 0 }-> 0 :|: z >= 0
   listify(z, z') -{ 5 + z' }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s') :|: s' >= 0, s' <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 4 + z' }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s'') :|: s'' >= 0, s'' <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 3 + z' }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s1) :|: s1 >= 0, s1 <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 5 + z' }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + 0), z', s14) :|: s14 >= 0, s14 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 6 + z' }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x1 + r''), z', s12) :|: s12 >= 0, s12 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r'', r1 >= 0, x1 >= 0, l1 >= 0, z = 1 + l1 + x1 + r1
   listify(z, z') -{ 5 + z' }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r''), z', s13) :|: s13 >= 0, s13 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 4 + z' }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s15) :|: s15 >= 0, s15 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 4 + z' }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', s18) :|: s18 >= 0, s18 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 5 + z' }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', s16) :|: s16 >= 0, s16 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 4 + z' }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', s17) :|: s17 >= 0, s17 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 3 + z' }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s19) :|: s19 >= 0, s19 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 4 + z' }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', s6) :|: s6 >= 0, s6 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 5 + z' }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', s4) :|: s4 >= 0, s4 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 4 + z' }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', s5) :|: s5 >= 0, s5 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 3 + z' }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s7) :|: s7 >= 0, s7 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x + 0), z', s10) :|: s10 >= 0, s10 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 4 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + r), z', s8) :|: s8 >= 0, s8 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 3 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r), z', s9) :|: s9 >= 0, s9 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 2 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s11) :|: s11 >= 0, s11 <= z' + z + 1, z >= 0, z' >= 0
   listify(z, z') -{ 4 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s2) :|: s2 >= 0, s2 <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 3 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s3) :|: s3 >= 0, s3 <= z' + z + 1, z >= 0, z' >= 0, z = 0
   right(z) -{ 1 }-> r :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   right(z) -{ 1 }-> 0 :|: z = 0
   right(z) -{ 0 }-> 0 :|: z >= 0
   toList(z) -{ 1 }-> listify(z, 0) :|: z >= 0

Function symbols to be analyzed: {left}, {listify,if}, {toList}
Previous analysis results are:
  isEmpty: runtime: O(1) [1], size: O(1) [2]
  elem: runtime: O(1) [1], size: O(n^1) [z]
  append: runtime: O(n^1) [1 + z], size: O(n^1) [1 + z + z']
  right: runtime: O(1) [1], size: O(n^1) [z]
  left: runtime: ?, size: O(n^1) [z]

----------------------------------------

(65) IntTrsBoundProof (UPPER BOUND(ID))

Computed RUNTIME bound using CoFloCo for: left
after applying outer abstraction to obtain an ITS,
resulting in: O(1) with polynomial bound: 1

----------------------------------------

(66)
Obligation:
Complexity RNTS consisting of the following rules:

   append(z, z') -{ 0 }-> 0 :|: z >= 0, z' >= 0
   append(z, z') -{ 1 }-> 1 + z' + 0 :|: z' >= 0, z = 0
   append(z, z') -{ z }-> 1 + 1 + s :|: s >= 0, s <= z - 2 + z' + 1, z - 2 >= 0, z' >= 0
   elem(z) -{ 1 }-> x :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   elem(z) -{ 0 }-> 0 :|: z >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> z2 :|: z = 2, z' >= 0, z'' >= 0, z2 >= 0, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z'', z3) :|: z'' >= 0, z2 >= 0, z' = 2, z = 1, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z1, z2) :|: z'' >= 0, z2 >= 0, z = 1, z3 >= 0, z' = 1, z1 >= 0
   isEmpty(z) -{ 1 }-> 2 :|: z = 0
   isEmpty(z) -{ 1 }-> 1 :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   isEmpty(z) -{ 0 }-> 0 :|: z >= 0
   left(z) -{ 1 }-> l :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   left(z) -{ 1 }-> 0 :|: z = 0
   left(z) -{ 0 }-> 0 :|: z >= 0
   listify(z, z') -{ 5 + z' }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s') :|: s' >= 0, s' <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 4 + z' }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s'') :|: s'' >= 0, s'' <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 3 + z' }-> if(2, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s1) :|: s1 >= 0, s1 <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 5 + z' }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + 0), z', s14) :|: s14 >= 0, s14 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 6 + z' }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x1 + r''), z', s12) :|: s12 >= 0, s12 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r'', r1 >= 0, x1 >= 0, l1 >= 0, z = 1 + l1 + x1 + r1
   listify(z, z') -{ 5 + z' }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r''), z', s13) :|: s13 >= 0, s13 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 4 + z' }-> if(1, isEmpty(left(z)), r', 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s15) :|: s15 >= 0, s15 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 4 + z' }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', s18) :|: s18 >= 0, s18 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 5 + z' }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', s16) :|: s16 >= 0, s16 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 4 + z' }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', s17) :|: s17 >= 0, s17 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 3 + z' }-> if(1, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s19) :|: s19 >= 0, s19 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 4 + z' }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + 0), z', s6) :|: s6 >= 0, s6 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 5 + z' }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x'' + r'), z', s4) :|: s4 >= 0, s4 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 4 + z' }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r'), z', s5) :|: s5 >= 0, s5 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 3 + z' }-> if(0, isEmpty(left(z)), r, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s7) :|: s7 >= 0, s7 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 3 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x + 0), z', s10) :|: s10 >= 0, s10 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 4 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + x' + r), z', s8) :|: s8 >= 0, s8 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 3 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + r), z', s9) :|: s9 >= 0, s9 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 2 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s11) :|: s11 >= 0, s11 <= z' + z + 1, z >= 0, z' >= 0
   listify(z, z') -{ 4 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s2) :|: s2 >= 0, s2 <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 3 + z' }-> if(0, isEmpty(left(z)), 0, 1 + left(left(z)) + elem(left(z)) + (1 + right(left(z)) + 0 + 0), z', s3) :|: s3 >= 0, s3 <= z' + z + 1, z >= 0, z' >= 0, z = 0
   right(z) -{ 1 }-> r :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   right(z) -{ 1 }-> 0 :|: z = 0
   right(z) -{ 0 }-> 0 :|: z >= 0
   toList(z) -{ 1 }-> listify(z, 0) :|: z >= 0

Function symbols to be analyzed: {listify,if}, {toList}
Previous analysis results are:
  isEmpty: runtime: O(1) [1], size: O(1) [2]
  elem: runtime: O(1) [1], size: O(n^1) [z]
  append: runtime: O(n^1) [1 + z], size: O(n^1) [1 + z + z']
  right: runtime: O(1) [1], size: O(n^1) [z]
  left: runtime: O(1) [1], size: O(n^1) [z]

----------------------------------------

(67) ResultPropagationProof (UPPER BOUND(ID))
Applied inner abstraction using the recently inferred runtime/size bounds where possible.
----------------------------------------

(68)
Obligation:
Complexity RNTS consisting of the following rules:

   append(z, z') -{ 0 }-> 0 :|: z >= 0, z' >= 0
   append(z, z') -{ 1 }-> 1 + z' + 0 :|: z' >= 0, z = 0
   append(z, z') -{ z }-> 1 + 1 + s :|: s >= 0, s <= z - 2 + z' + 1, z - 2 >= 0, z' >= 0
   elem(z) -{ 1 }-> x :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   elem(z) -{ 0 }-> 0 :|: z >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> z2 :|: z = 2, z' >= 0, z'' >= 0, z2 >= 0, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z'', z3) :|: z'' >= 0, z2 >= 0, z' = 2, z = 1, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z1, z2) :|: z'' >= 0, z2 >= 0, z = 1, z3 >= 0, z' = 1, z1 >= 0
   isEmpty(z) -{ 1 }-> 2 :|: z = 0
   isEmpty(z) -{ 1 }-> 1 :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   isEmpty(z) -{ 0 }-> 0 :|: z >= 0
   left(z) -{ 1 }-> l :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   left(z) -{ 1 }-> 0 :|: z = 0
   left(z) -{ 0 }-> 0 :|: z >= 0
   listify(z, z') -{ 13 + z' }-> if(2, s21, 0, 1 + s23 + s25 + (1 + s27 + 0 + 0), z', s') :|: s20 >= 0, s20 <= z, s21 >= 0, s21 <= 2, s22 >= 0, s22 <= z, s23 >= 0, s23 <= s22, s24 >= 0, s24 <= z, s25 >= 0, s25 <= s24, s26 >= 0, s26 <= z, s27 >= 0, s27 <= s26, s' >= 0, s' <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 12 + z' }-> if(2, s29, 0, 1 + s31 + s33 + (1 + s35 + 0 + 0), z', s'') :|: s28 >= 0, s28 <= z, s29 >= 0, s29 <= 2, s30 >= 0, s30 <= z, s31 >= 0, s31 <= s30, s32 >= 0, s32 <= z, s33 >= 0, s33 <= s32, s34 >= 0, s34 <= z, s35 >= 0, s35 <= s34, s'' >= 0, s'' <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 11 + z' }-> if(2, s37, 0, 1 + s39 + s41 + (1 + s43 + 0 + 0), z', s1) :|: s36 >= 0, s36 <= z, s37 >= 0, s37 <= 2, s38 >= 0, s38 <= z, s39 >= 0, s39 <= s38, s40 >= 0, s40 <= z, s41 >= 0, s41 <= s40, s42 >= 0, s42 <= z, s43 >= 0, s43 <= s42, s1 >= 0, s1 <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 14 + z' }-> if(1, s125, r', 1 + s127 + s129 + (1 + s131 + x1 + r''), z', s12) :|: s124 >= 0, s124 <= z, s125 >= 0, s125 <= 2, s126 >= 0, s126 <= z, s127 >= 0, s127 <= s126, s128 >= 0, s128 <= z, s129 >= 0, s129 <= s128, s130 >= 0, s130 <= z, s131 >= 0, s131 <= s130, s12 >= 0, s12 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r'', r1 >= 0, x1 >= 0, l1 >= 0, z = 1 + l1 + x1 + r1
   listify(z, z') -{ 13 + z' }-> if(1, s133, r', 1 + s135 + s137 + (1 + s139 + 0 + r''), z', s13) :|: s132 >= 0, s132 <= z, s133 >= 0, s133 <= 2, s134 >= 0, s134 <= z, s135 >= 0, s135 <= s134, s136 >= 0, s136 <= z, s137 >= 0, s137 <= s136, s138 >= 0, s138 <= z, s139 >= 0, s139 <= s138, s13 >= 0, s13 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 13 + z' }-> if(1, s141, r', 1 + s143 + s145 + (1 + s147 + x'' + 0), z', s14) :|: s140 >= 0, s140 <= z, s141 >= 0, s141 <= 2, s142 >= 0, s142 <= z, s143 >= 0, s143 <= s142, s144 >= 0, s144 <= z, s145 >= 0, s145 <= s144, s146 >= 0, s146 <= z, s147 >= 0, s147 <= s146, s14 >= 0, s14 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 12 + z' }-> if(1, s149, r', 1 + s151 + s153 + (1 + s155 + 0 + 0), z', s15) :|: s148 >= 0, s148 <= z, s149 >= 0, s149 <= 2, s150 >= 0, s150 <= z, s151 >= 0, s151 <= s150, s152 >= 0, s152 <= z, s153 >= 0, s153 <= s152, s154 >= 0, s154 <= z, s155 >= 0, s155 <= s154, s15 >= 0, s15 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 13 + z' }-> if(1, s157, 0, 1 + s159 + s161 + (1 + s163 + x'' + r'), z', s16) :|: s156 >= 0, s156 <= z, s157 >= 0, s157 <= 2, s158 >= 0, s158 <= z, s159 >= 0, s159 <= s158, s160 >= 0, s160 <= z, s161 >= 0, s161 <= s160, s162 >= 0, s162 <= z, s163 >= 0, s163 <= s162, s16 >= 0, s16 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 12 + z' }-> if(1, s165, 0, 1 + s167 + s169 + (1 + s171 + 0 + r'), z', s17) :|: s164 >= 0, s164 <= z, s165 >= 0, s165 <= 2, s166 >= 0, s166 <= z, s167 >= 0, s167 <= s166, s168 >= 0, s168 <= z, s169 >= 0, s169 <= s168, s170 >= 0, s170 <= z, s171 >= 0, s171 <= s170, s17 >= 0, s17 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 12 + z' }-> if(1, s173, 0, 1 + s175 + s177 + (1 + s179 + x' + 0), z', s18) :|: s172 >= 0, s172 <= z, s173 >= 0, s173 <= 2, s174 >= 0, s174 <= z, s175 >= 0, s175 <= s174, s176 >= 0, s176 <= z, s177 >= 0, s177 <= s176, s178 >= 0, s178 <= z, s179 >= 0, s179 <= s178, s18 >= 0, s18 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 11 + z' }-> if(1, s181, 0, 1 + s183 + s185 + (1 + s187 + 0 + 0), z', s19) :|: s180 >= 0, s180 <= z, s181 >= 0, s181 <= 2, s182 >= 0, s182 <= z, s183 >= 0, s183 <= s182, s184 >= 0, s184 <= z, s185 >= 0, s185 <= s184, s186 >= 0, s186 <= z, s187 >= 0, s187 <= s186, s19 >= 0, s19 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 11 + z' }-> if(0, s101, 0, 1 + s103 + s105 + (1 + s107 + 0 + r), z', s9) :|: s100 >= 0, s100 <= z, s101 >= 0, s101 <= 2, s102 >= 0, s102 <= z, s103 >= 0, s103 <= s102, s104 >= 0, s104 <= z, s105 >= 0, s105 <= s104, s106 >= 0, s106 <= z, s107 >= 0, s107 <= s106, s9 >= 0, s9 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 11 + z' }-> if(0, s109, 0, 1 + s111 + s113 + (1 + s115 + x + 0), z', s10) :|: s108 >= 0, s108 <= z, s109 >= 0, s109 <= 2, s110 >= 0, s110 <= z, s111 >= 0, s111 <= s110, s112 >= 0, s112 <= z, s113 >= 0, s113 <= s112, s114 >= 0, s114 <= z, s115 >= 0, s115 <= s114, s10 >= 0, s10 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 10 + z' }-> if(0, s117, 0, 1 + s119 + s121 + (1 + s123 + 0 + 0), z', s11) :|: s116 >= 0, s116 <= z, s117 >= 0, s117 <= 2, s118 >= 0, s118 <= z, s119 >= 0, s119 <= s118, s120 >= 0, s120 <= z, s121 >= 0, s121 <= s120, s122 >= 0, s122 <= z, s123 >= 0, s123 <= s122, s11 >= 0, s11 <= z' + z + 1, z >= 0, z' >= 0
   listify(z, z') -{ 12 + z' }-> if(0, s45, 0, 1 + s47 + s49 + (1 + s51 + 0 + 0), z', s2) :|: s44 >= 0, s44 <= z, s45 >= 0, s45 <= 2, s46 >= 0, s46 <= z, s47 >= 0, s47 <= s46, s48 >= 0, s48 <= z, s49 >= 0, s49 <= s48, s50 >= 0, s50 <= z, s51 >= 0, s51 <= s50, s2 >= 0, s2 <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 11 + z' }-> if(0, s53, 0, 1 + s55 + s57 + (1 + s59 + 0 + 0), z', s3) :|: s52 >= 0, s52 <= z, s53 >= 0, s53 <= 2, s54 >= 0, s54 <= z, s55 >= 0, s55 <= s54, s56 >= 0, s56 <= z, s57 >= 0, s57 <= s56, s58 >= 0, s58 <= z, s59 >= 0, s59 <= s58, s3 >= 0, s3 <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 13 + z' }-> if(0, s61, r, 1 + s63 + s65 + (1 + s67 + x'' + r'), z', s4) :|: s60 >= 0, s60 <= z, s61 >= 0, s61 <= 2, s62 >= 0, s62 <= z, s63 >= 0, s63 <= s62, s64 >= 0, s64 <= z, s65 >= 0, s65 <= s64, s66 >= 0, s66 <= z, s67 >= 0, s67 <= s66, s4 >= 0, s4 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 12 + z' }-> if(0, s69, r, 1 + s71 + s73 + (1 + s75 + 0 + r'), z', s5) :|: s68 >= 0, s68 <= z, s69 >= 0, s69 <= 2, s70 >= 0, s70 <= z, s71 >= 0, s71 <= s70, s72 >= 0, s72 <= z, s73 >= 0, s73 <= s72, s74 >= 0, s74 <= z, s75 >= 0, s75 <= s74, s5 >= 0, s5 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 12 + z' }-> if(0, s77, r, 1 + s79 + s81 + (1 + s83 + x' + 0), z', s6) :|: s76 >= 0, s76 <= z, s77 >= 0, s77 <= 2, s78 >= 0, s78 <= z, s79 >= 0, s79 <= s78, s80 >= 0, s80 <= z, s81 >= 0, s81 <= s80, s82 >= 0, s82 <= z, s83 >= 0, s83 <= s82, s6 >= 0, s6 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 11 + z' }-> if(0, s85, r, 1 + s87 + s89 + (1 + s91 + 0 + 0), z', s7) :|: s84 >= 0, s84 <= z, s85 >= 0, s85 <= 2, s86 >= 0, s86 <= z, s87 >= 0, s87 <= s86, s88 >= 0, s88 <= z, s89 >= 0, s89 <= s88, s90 >= 0, s90 <= z, s91 >= 0, s91 <= s90, s7 >= 0, s7 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 12 + z' }-> if(0, s93, 0, 1 + s95 + s97 + (1 + s99 + x' + r), z', s8) :|: s92 >= 0, s92 <= z, s93 >= 0, s93 <= 2, s94 >= 0, s94 <= z, s95 >= 0, s95 <= s94, s96 >= 0, s96 <= z, s97 >= 0, s97 <= s96, s98 >= 0, s98 <= z, s99 >= 0, s99 <= s98, s8 >= 0, s8 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   right(z) -{ 1 }-> r :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   right(z) -{ 1 }-> 0 :|: z = 0
   right(z) -{ 0 }-> 0 :|: z >= 0
   toList(z) -{ 1 }-> listify(z, 0) :|: z >= 0

Function symbols to be analyzed: {listify,if}, {toList}
Previous analysis results are:
  isEmpty: runtime: O(1) [1], size: O(1) [2]
  elem: runtime: O(1) [1], size: O(n^1) [z]
  append: runtime: O(n^1) [1 + z], size: O(n^1) [1 + z + z']
  right: runtime: O(1) [1], size: O(n^1) [z]
  left: runtime: O(1) [1], size: O(n^1) [z]

----------------------------------------

(69) IntTrsBoundProof (UPPER BOUND(ID))

Computed SIZE bound using CoFloCo for: listify
after applying outer abstraction to obtain an ITS,
resulting in: INF with polynomial bound: ?

Computed SIZE bound using CoFloCo for: if
after applying outer abstraction to obtain an ITS,
resulting in: INF with polynomial bound: ?

----------------------------------------

(70)
Obligation:
Complexity RNTS consisting of the following rules:

   append(z, z') -{ 0 }-> 0 :|: z >= 0, z' >= 0
   append(z, z') -{ 1 }-> 1 + z' + 0 :|: z' >= 0, z = 0
   append(z, z') -{ z }-> 1 + 1 + s :|: s >= 0, s <= z - 2 + z' + 1, z - 2 >= 0, z' >= 0
   elem(z) -{ 1 }-> x :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   elem(z) -{ 0 }-> 0 :|: z >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> z2 :|: z = 2, z' >= 0, z'' >= 0, z2 >= 0, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z'', z3) :|: z'' >= 0, z2 >= 0, z' = 2, z = 1, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z1, z2) :|: z'' >= 0, z2 >= 0, z = 1, z3 >= 0, z' = 1, z1 >= 0
   isEmpty(z) -{ 1 }-> 2 :|: z = 0
   isEmpty(z) -{ 1 }-> 1 :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   isEmpty(z) -{ 0 }-> 0 :|: z >= 0
   left(z) -{ 1 }-> l :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   left(z) -{ 1 }-> 0 :|: z = 0
   left(z) -{ 0 }-> 0 :|: z >= 0
   listify(z, z') -{ 13 + z' }-> if(2, s21, 0, 1 + s23 + s25 + (1 + s27 + 0 + 0), z', s') :|: s20 >= 0, s20 <= z, s21 >= 0, s21 <= 2, s22 >= 0, s22 <= z, s23 >= 0, s23 <= s22, s24 >= 0, s24 <= z, s25 >= 0, s25 <= s24, s26 >= 0, s26 <= z, s27 >= 0, s27 <= s26, s' >= 0, s' <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 12 + z' }-> if(2, s29, 0, 1 + s31 + s33 + (1 + s35 + 0 + 0), z', s'') :|: s28 >= 0, s28 <= z, s29 >= 0, s29 <= 2, s30 >= 0, s30 <= z, s31 >= 0, s31 <= s30, s32 >= 0, s32 <= z, s33 >= 0, s33 <= s32, s34 >= 0, s34 <= z, s35 >= 0, s35 <= s34, s'' >= 0, s'' <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 11 + z' }-> if(2, s37, 0, 1 + s39 + s41 + (1 + s43 + 0 + 0), z', s1) :|: s36 >= 0, s36 <= z, s37 >= 0, s37 <= 2, s38 >= 0, s38 <= z, s39 >= 0, s39 <= s38, s40 >= 0, s40 <= z, s41 >= 0, s41 <= s40, s42 >= 0, s42 <= z, s43 >= 0, s43 <= s42, s1 >= 0, s1 <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 14 + z' }-> if(1, s125, r', 1 + s127 + s129 + (1 + s131 + x1 + r''), z', s12) :|: s124 >= 0, s124 <= z, s125 >= 0, s125 <= 2, s126 >= 0, s126 <= z, s127 >= 0, s127 <= s126, s128 >= 0, s128 <= z, s129 >= 0, s129 <= s128, s130 >= 0, s130 <= z, s131 >= 0, s131 <= s130, s12 >= 0, s12 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r'', r1 >= 0, x1 >= 0, l1 >= 0, z = 1 + l1 + x1 + r1
   listify(z, z') -{ 13 + z' }-> if(1, s133, r', 1 + s135 + s137 + (1 + s139 + 0 + r''), z', s13) :|: s132 >= 0, s132 <= z, s133 >= 0, s133 <= 2, s134 >= 0, s134 <= z, s135 >= 0, s135 <= s134, s136 >= 0, s136 <= z, s137 >= 0, s137 <= s136, s138 >= 0, s138 <= z, s139 >= 0, s139 <= s138, s13 >= 0, s13 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 13 + z' }-> if(1, s141, r', 1 + s143 + s145 + (1 + s147 + x'' + 0), z', s14) :|: s140 >= 0, s140 <= z, s141 >= 0, s141 <= 2, s142 >= 0, s142 <= z, s143 >= 0, s143 <= s142, s144 >= 0, s144 <= z, s145 >= 0, s145 <= s144, s146 >= 0, s146 <= z, s147 >= 0, s147 <= s146, s14 >= 0, s14 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 12 + z' }-> if(1, s149, r', 1 + s151 + s153 + (1 + s155 + 0 + 0), z', s15) :|: s148 >= 0, s148 <= z, s149 >= 0, s149 <= 2, s150 >= 0, s150 <= z, s151 >= 0, s151 <= s150, s152 >= 0, s152 <= z, s153 >= 0, s153 <= s152, s154 >= 0, s154 <= z, s155 >= 0, s155 <= s154, s15 >= 0, s15 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 13 + z' }-> if(1, s157, 0, 1 + s159 + s161 + (1 + s163 + x'' + r'), z', s16) :|: s156 >= 0, s156 <= z, s157 >= 0, s157 <= 2, s158 >= 0, s158 <= z, s159 >= 0, s159 <= s158, s160 >= 0, s160 <= z, s161 >= 0, s161 <= s160, s162 >= 0, s162 <= z, s163 >= 0, s163 <= s162, s16 >= 0, s16 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 12 + z' }-> if(1, s165, 0, 1 + s167 + s169 + (1 + s171 + 0 + r'), z', s17) :|: s164 >= 0, s164 <= z, s165 >= 0, s165 <= 2, s166 >= 0, s166 <= z, s167 >= 0, s167 <= s166, s168 >= 0, s168 <= z, s169 >= 0, s169 <= s168, s170 >= 0, s170 <= z, s171 >= 0, s171 <= s170, s17 >= 0, s17 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 12 + z' }-> if(1, s173, 0, 1 + s175 + s177 + (1 + s179 + x' + 0), z', s18) :|: s172 >= 0, s172 <= z, s173 >= 0, s173 <= 2, s174 >= 0, s174 <= z, s175 >= 0, s175 <= s174, s176 >= 0, s176 <= z, s177 >= 0, s177 <= s176, s178 >= 0, s178 <= z, s179 >= 0, s179 <= s178, s18 >= 0, s18 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 11 + z' }-> if(1, s181, 0, 1 + s183 + s185 + (1 + s187 + 0 + 0), z', s19) :|: s180 >= 0, s180 <= z, s181 >= 0, s181 <= 2, s182 >= 0, s182 <= z, s183 >= 0, s183 <= s182, s184 >= 0, s184 <= z, s185 >= 0, s185 <= s184, s186 >= 0, s186 <= z, s187 >= 0, s187 <= s186, s19 >= 0, s19 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 11 + z' }-> if(0, s101, 0, 1 + s103 + s105 + (1 + s107 + 0 + r), z', s9) :|: s100 >= 0, s100 <= z, s101 >= 0, s101 <= 2, s102 >= 0, s102 <= z, s103 >= 0, s103 <= s102, s104 >= 0, s104 <= z, s105 >= 0, s105 <= s104, s106 >= 0, s106 <= z, s107 >= 0, s107 <= s106, s9 >= 0, s9 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 11 + z' }-> if(0, s109, 0, 1 + s111 + s113 + (1 + s115 + x + 0), z', s10) :|: s108 >= 0, s108 <= z, s109 >= 0, s109 <= 2, s110 >= 0, s110 <= z, s111 >= 0, s111 <= s110, s112 >= 0, s112 <= z, s113 >= 0, s113 <= s112, s114 >= 0, s114 <= z, s115 >= 0, s115 <= s114, s10 >= 0, s10 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 10 + z' }-> if(0, s117, 0, 1 + s119 + s121 + (1 + s123 + 0 + 0), z', s11) :|: s116 >= 0, s116 <= z, s117 >= 0, s117 <= 2, s118 >= 0, s118 <= z, s119 >= 0, s119 <= s118, s120 >= 0, s120 <= z, s121 >= 0, s121 <= s120, s122 >= 0, s122 <= z, s123 >= 0, s123 <= s122, s11 >= 0, s11 <= z' + z + 1, z >= 0, z' >= 0
   listify(z, z') -{ 12 + z' }-> if(0, s45, 0, 1 + s47 + s49 + (1 + s51 + 0 + 0), z', s2) :|: s44 >= 0, s44 <= z, s45 >= 0, s45 <= 2, s46 >= 0, s46 <= z, s47 >= 0, s47 <= s46, s48 >= 0, s48 <= z, s49 >= 0, s49 <= s48, s50 >= 0, s50 <= z, s51 >= 0, s51 <= s50, s2 >= 0, s2 <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 11 + z' }-> if(0, s53, 0, 1 + s55 + s57 + (1 + s59 + 0 + 0), z', s3) :|: s52 >= 0, s52 <= z, s53 >= 0, s53 <= 2, s54 >= 0, s54 <= z, s55 >= 0, s55 <= s54, s56 >= 0, s56 <= z, s57 >= 0, s57 <= s56, s58 >= 0, s58 <= z, s59 >= 0, s59 <= s58, s3 >= 0, s3 <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 13 + z' }-> if(0, s61, r, 1 + s63 + s65 + (1 + s67 + x'' + r'), z', s4) :|: s60 >= 0, s60 <= z, s61 >= 0, s61 <= 2, s62 >= 0, s62 <= z, s63 >= 0, s63 <= s62, s64 >= 0, s64 <= z, s65 >= 0, s65 <= s64, s66 >= 0, s66 <= z, s67 >= 0, s67 <= s66, s4 >= 0, s4 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 12 + z' }-> if(0, s69, r, 1 + s71 + s73 + (1 + s75 + 0 + r'), z', s5) :|: s68 >= 0, s68 <= z, s69 >= 0, s69 <= 2, s70 >= 0, s70 <= z, s71 >= 0, s71 <= s70, s72 >= 0, s72 <= z, s73 >= 0, s73 <= s72, s74 >= 0, s74 <= z, s75 >= 0, s75 <= s74, s5 >= 0, s5 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 12 + z' }-> if(0, s77, r, 1 + s79 + s81 + (1 + s83 + x' + 0), z', s6) :|: s76 >= 0, s76 <= z, s77 >= 0, s77 <= 2, s78 >= 0, s78 <= z, s79 >= 0, s79 <= s78, s80 >= 0, s80 <= z, s81 >= 0, s81 <= s80, s82 >= 0, s82 <= z, s83 >= 0, s83 <= s82, s6 >= 0, s6 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 11 + z' }-> if(0, s85, r, 1 + s87 + s89 + (1 + s91 + 0 + 0), z', s7) :|: s84 >= 0, s84 <= z, s85 >= 0, s85 <= 2, s86 >= 0, s86 <= z, s87 >= 0, s87 <= s86, s88 >= 0, s88 <= z, s89 >= 0, s89 <= s88, s90 >= 0, s90 <= z, s91 >= 0, s91 <= s90, s7 >= 0, s7 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 12 + z' }-> if(0, s93, 0, 1 + s95 + s97 + (1 + s99 + x' + r), z', s8) :|: s92 >= 0, s92 <= z, s93 >= 0, s93 <= 2, s94 >= 0, s94 <= z, s95 >= 0, s95 <= s94, s96 >= 0, s96 <= z, s97 >= 0, s97 <= s96, s98 >= 0, s98 <= z, s99 >= 0, s99 <= s98, s8 >= 0, s8 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   right(z) -{ 1 }-> r :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   right(z) -{ 1 }-> 0 :|: z = 0
   right(z) -{ 0 }-> 0 :|: z >= 0
   toList(z) -{ 1 }-> listify(z, 0) :|: z >= 0

Function symbols to be analyzed: {listify,if}, {toList}
Previous analysis results are:
  isEmpty: runtime: O(1) [1], size: O(1) [2]
  elem: runtime: O(1) [1], size: O(n^1) [z]
  append: runtime: O(n^1) [1 + z], size: O(n^1) [1 + z + z']
  right: runtime: O(1) [1], size: O(n^1) [z]
  left: runtime: O(1) [1], size: O(n^1) [z]
  listify: runtime: ?, size: INF
  if: runtime: ?, size: INF

----------------------------------------

(71) IntTrsBoundProof (UPPER BOUND(ID))

Computed RUNTIME bound using CoFloCo for: listify
after applying outer abstraction to obtain an ITS,
resulting in: INF with polynomial bound: ?

----------------------------------------

(72)
Obligation:
Complexity RNTS consisting of the following rules:

   append(z, z') -{ 0 }-> 0 :|: z >= 0, z' >= 0
   append(z, z') -{ 1 }-> 1 + z' + 0 :|: z' >= 0, z = 0
   append(z, z') -{ z }-> 1 + 1 + s :|: s >= 0, s <= z - 2 + z' + 1, z - 2 >= 0, z' >= 0
   elem(z) -{ 1 }-> x :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   elem(z) -{ 0 }-> 0 :|: z >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> z2 :|: z = 2, z' >= 0, z'' >= 0, z2 >= 0, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z'', z3) :|: z'' >= 0, z2 >= 0, z' = 2, z = 1, z3 >= 0, z1 >= 0
   if(z, z', z'', z1, z2, z3) -{ 1 }-> listify(z1, z2) :|: z'' >= 0, z2 >= 0, z = 1, z3 >= 0, z' = 1, z1 >= 0
   isEmpty(z) -{ 1 }-> 2 :|: z = 0
   isEmpty(z) -{ 1 }-> 1 :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   isEmpty(z) -{ 0 }-> 0 :|: z >= 0
   left(z) -{ 1 }-> l :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   left(z) -{ 1 }-> 0 :|: z = 0
   left(z) -{ 0 }-> 0 :|: z >= 0
   listify(z, z') -{ 13 + z' }-> if(2, s21, 0, 1 + s23 + s25 + (1 + s27 + 0 + 0), z', s') :|: s20 >= 0, s20 <= z, s21 >= 0, s21 <= 2, s22 >= 0, s22 <= z, s23 >= 0, s23 <= s22, s24 >= 0, s24 <= z, s25 >= 0, s25 <= s24, s26 >= 0, s26 <= z, s27 >= 0, s27 <= s26, s' >= 0, s' <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 12 + z' }-> if(2, s29, 0, 1 + s31 + s33 + (1 + s35 + 0 + 0), z', s'') :|: s28 >= 0, s28 <= z, s29 >= 0, s29 <= 2, s30 >= 0, s30 <= z, s31 >= 0, s31 <= s30, s32 >= 0, s32 <= z, s33 >= 0, s33 <= s32, s34 >= 0, s34 <= z, s35 >= 0, s35 <= s34, s'' >= 0, s'' <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 11 + z' }-> if(2, s37, 0, 1 + s39 + s41 + (1 + s43 + 0 + 0), z', s1) :|: s36 >= 0, s36 <= z, s37 >= 0, s37 <= 2, s38 >= 0, s38 <= z, s39 >= 0, s39 <= s38, s40 >= 0, s40 <= z, s41 >= 0, s41 <= s40, s42 >= 0, s42 <= z, s43 >= 0, s43 <= s42, s1 >= 0, s1 <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 14 + z' }-> if(1, s125, r', 1 + s127 + s129 + (1 + s131 + x1 + r''), z', s12) :|: s124 >= 0, s124 <= z, s125 >= 0, s125 <= 2, s126 >= 0, s126 <= z, s127 >= 0, s127 <= s126, s128 >= 0, s128 <= z, s129 >= 0, s129 <= s128, s130 >= 0, s130 <= z, s131 >= 0, s131 <= s130, s12 >= 0, s12 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r'', r1 >= 0, x1 >= 0, l1 >= 0, z = 1 + l1 + x1 + r1
   listify(z, z') -{ 13 + z' }-> if(1, s133, r', 1 + s135 + s137 + (1 + s139 + 0 + r''), z', s13) :|: s132 >= 0, s132 <= z, s133 >= 0, s133 <= 2, s134 >= 0, s134 <= z, s135 >= 0, s135 <= s134, s136 >= 0, s136 <= z, s137 >= 0, s137 <= s136, s138 >= 0, s138 <= z, s139 >= 0, s139 <= s138, s13 >= 0, s13 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 13 + z' }-> if(1, s141, r', 1 + s143 + s145 + (1 + s147 + x'' + 0), z', s14) :|: s140 >= 0, s140 <= z, s141 >= 0, s141 <= 2, s142 >= 0, s142 <= z, s143 >= 0, s143 <= s142, s144 >= 0, s144 <= z, s145 >= 0, s145 <= s144, s146 >= 0, s146 <= z, s147 >= 0, s147 <= s146, s14 >= 0, s14 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 12 + z' }-> if(1, s149, r', 1 + s151 + s153 + (1 + s155 + 0 + 0), z', s15) :|: s148 >= 0, s148 <= z, s149 >= 0, s149 <= 2, s150 >= 0, s150 <= z, s151 >= 0, s151 <= s150, s152 >= 0, s152 <= z, s153 >= 0, s153 <= s152, s154 >= 0, s154 <= z, s155 >= 0, s155 <= s154, s15 >= 0, s15 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 13 + z' }-> if(1, s157, 0, 1 + s159 + s161 + (1 + s163 + x'' + r'), z', s16) :|: s156 >= 0, s156 <= z, s157 >= 0, s157 <= 2, s158 >= 0, s158 <= z, s159 >= 0, s159 <= s158, s160 >= 0, s160 <= z, s161 >= 0, s161 <= s160, s162 >= 0, s162 <= z, s163 >= 0, s163 <= s162, s16 >= 0, s16 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 12 + z' }-> if(1, s165, 0, 1 + s167 + s169 + (1 + s171 + 0 + r'), z', s17) :|: s164 >= 0, s164 <= z, s165 >= 0, s165 <= 2, s166 >= 0, s166 <= z, s167 >= 0, s167 <= s166, s168 >= 0, s168 <= z, s169 >= 0, s169 <= s168, s170 >= 0, s170 <= z, s171 >= 0, s171 <= s170, s17 >= 0, s17 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 12 + z' }-> if(1, s173, 0, 1 + s175 + s177 + (1 + s179 + x' + 0), z', s18) :|: s172 >= 0, s172 <= z, s173 >= 0, s173 <= 2, s174 >= 0, s174 <= z, s175 >= 0, s175 <= s174, s176 >= 0, s176 <= z, s177 >= 0, s177 <= s176, s178 >= 0, s178 <= z, s179 >= 0, s179 <= s178, s18 >= 0, s18 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 11 + z' }-> if(1, s181, 0, 1 + s183 + s185 + (1 + s187 + 0 + 0), z', s19) :|: s180 >= 0, s180 <= z, s181 >= 0, s181 <= 2, s182 >= 0, s182 <= z, s183 >= 0, s183 <= s182, s184 >= 0, s184 <= z, s185 >= 0, s185 <= s184, s186 >= 0, s186 <= z, s187 >= 0, s187 <= s186, s19 >= 0, s19 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 11 + z' }-> if(0, s101, 0, 1 + s103 + s105 + (1 + s107 + 0 + r), z', s9) :|: s100 >= 0, s100 <= z, s101 >= 0, s101 <= 2, s102 >= 0, s102 <= z, s103 >= 0, s103 <= s102, s104 >= 0, s104 <= z, s105 >= 0, s105 <= s104, s106 >= 0, s106 <= z, s107 >= 0, s107 <= s106, s9 >= 0, s9 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 11 + z' }-> if(0, s109, 0, 1 + s111 + s113 + (1 + s115 + x + 0), z', s10) :|: s108 >= 0, s108 <= z, s109 >= 0, s109 <= 2, s110 >= 0, s110 <= z, s111 >= 0, s111 <= s110, s112 >= 0, s112 <= z, s113 >= 0, s113 <= s112, s114 >= 0, s114 <= z, s115 >= 0, s115 <= s114, s10 >= 0, s10 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 10 + z' }-> if(0, s117, 0, 1 + s119 + s121 + (1 + s123 + 0 + 0), z', s11) :|: s116 >= 0, s116 <= z, s117 >= 0, s117 <= 2, s118 >= 0, s118 <= z, s119 >= 0, s119 <= s118, s120 >= 0, s120 <= z, s121 >= 0, s121 <= s120, s122 >= 0, s122 <= z, s123 >= 0, s123 <= s122, s11 >= 0, s11 <= z' + z + 1, z >= 0, z' >= 0
   listify(z, z') -{ 12 + z' }-> if(0, s45, 0, 1 + s47 + s49 + (1 + s51 + 0 + 0), z', s2) :|: s44 >= 0, s44 <= z, s45 >= 0, s45 <= 2, s46 >= 0, s46 <= z, s47 >= 0, s47 <= s46, s48 >= 0, s48 <= z, s49 >= 0, s49 <= s48, s50 >= 0, s50 <= z, s51 >= 0, s51 <= s50, s2 >= 0, s2 <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 11 + z' }-> if(0, s53, 0, 1 + s55 + s57 + (1 + s59 + 0 + 0), z', s3) :|: s52 >= 0, s52 <= z, s53 >= 0, s53 <= 2, s54 >= 0, s54 <= z, s55 >= 0, s55 <= s54, s56 >= 0, s56 <= z, s57 >= 0, s57 <= s56, s58 >= 0, s58 <= z, s59 >= 0, s59 <= s58, s3 >= 0, s3 <= z' + z + 1, z >= 0, z' >= 0, z = 0
   listify(z, z') -{ 13 + z' }-> if(0, s61, r, 1 + s63 + s65 + (1 + s67 + x'' + r'), z', s4) :|: s60 >= 0, s60 <= z, s61 >= 0, s61 <= 2, s62 >= 0, s62 <= z, s63 >= 0, s63 <= s62, s64 >= 0, s64 <= z, s65 >= 0, s65 <= s64, s66 >= 0, s66 <= z, s67 >= 0, s67 <= s66, s4 >= 0, s4 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r', r'' >= 0, x'' >= 0, l'' >= 0, z = 1 + l'' + x'' + r''
   listify(z, z') -{ 12 + z' }-> if(0, s69, r, 1 + s71 + s73 + (1 + s75 + 0 + r'), z', s5) :|: s68 >= 0, s68 <= z, s69 >= 0, s69 <= 2, s70 >= 0, s70 <= z, s71 >= 0, s71 <= s70, s72 >= 0, s72 <= z, s73 >= 0, s73 <= s72, s74 >= 0, s74 <= z, s75 >= 0, s75 <= s74, s5 >= 0, s5 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 12 + z' }-> if(0, s77, r, 1 + s79 + s81 + (1 + s83 + x' + 0), z', s6) :|: s76 >= 0, s76 <= z, s77 >= 0, s77 <= 2, s78 >= 0, s78 <= z, s79 >= 0, s79 <= s78, s80 >= 0, s80 <= z, s81 >= 0, s81 <= s80, s82 >= 0, s82 <= z, s83 >= 0, s83 <= s82, s6 >= 0, s6 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   listify(z, z') -{ 11 + z' }-> if(0, s85, r, 1 + s87 + s89 + (1 + s91 + 0 + 0), z', s7) :|: s84 >= 0, s84 <= z, s85 >= 0, s85 <= 2, s86 >= 0, s86 <= z, s87 >= 0, s87 <= s86, s88 >= 0, s88 <= z, s89 >= 0, s89 <= s88, s90 >= 0, s90 <= z, s91 >= 0, s91 <= s90, s7 >= 0, s7 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   listify(z, z') -{ 12 + z' }-> if(0, s93, 0, 1 + s95 + s97 + (1 + s99 + x' + r), z', s8) :|: s92 >= 0, s92 <= z, s93 >= 0, s93 <= 2, s94 >= 0, s94 <= z, s95 >= 0, s95 <= s94, s96 >= 0, s96 <= z, s97 >= 0, s97 <= s96, s98 >= 0, s98 <= z, s99 >= 0, s99 <= s98, s8 >= 0, s8 <= z' + z + 1, z >= 0, z' >= 0, r >= 0, x >= 0, l >= 0, z = 1 + l + x + r, r' >= 0, x' >= 0, l' >= 0, z = 1 + l' + x' + r'
   right(z) -{ 1 }-> r :|: r >= 0, x >= 0, l >= 0, z = 1 + l + x + r
   right(z) -{ 1 }-> 0 :|: z = 0
   right(z) -{ 0 }-> 0 :|: z >= 0
   toList(z) -{ 1 }-> listify(z, 0) :|: z >= 0

Function symbols to be analyzed: {listify,if}, {toList}
Previous analysis results are:
  isEmpty: runtime: O(1) [1], size: O(1) [2]
  elem: runtime: O(1) [1], size: O(n^1) [z]
  append: runtime: O(n^1) [1 + z], size: O(n^1) [1 + z + z']
  right: runtime: O(1) [1], size: O(n^1) [z]
  left: runtime: O(1) [1], size: O(n^1) [z]
  listify: runtime: INF, size: INF
  if: runtime: ?, size: INF

----------------------------------------

(73) CpxTrsToCdtProof (UPPER BOUND(ID))
Converted Cpx (relative) TRS with rewrite strategy PARALLEL_INNERMOST to CDT
----------------------------------------

(74)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
   listify(z0, z1) -> if(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))
   if(true, z0, z1, z2, z3, z4) -> z3
   if(false, false, z0, z1, z2, z3) -> listify(z1, z2)
   if(false, true, z0, z1, z2, z3) -> listify(z0, z3)
   toList(z0) -> listify(z0, nil)
Tuples:
   ISEMPTY(empty) -> c
   ISEMPTY(node(z0, z1, z2)) -> c1
   LEFT(empty) -> c2
   LEFT(node(z0, z1, z2)) -> c3
   RIGHT(empty) -> c4
   RIGHT(node(z0, z1, z2)) -> c5
   ELEM(node(z0, z1, z2)) -> c6
   APPEND(nil, z0) -> c7
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   LISTIFY(z0, z1) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ISEMPTY(z0))
   LISTIFY(z0, z1) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ISEMPTY(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), RIGHT(z0))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), LEFT(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ELEM(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), RIGHT(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ELEM(z0))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), RIGHT(z0))
   LISTIFY(z0, z1) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), APPEND(z1, z0))
   IF(true, z0, z1, z2, z3, z4) -> c18
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   TOLIST(z0) -> c21(LISTIFY(z0, nil))
S tuples:
   ISEMPTY(empty) -> c
   ISEMPTY(node(z0, z1, z2)) -> c1
   LEFT(empty) -> c2
   LEFT(node(z0, z1, z2)) -> c3
   RIGHT(empty) -> c4
   RIGHT(node(z0, z1, z2)) -> c5
   ELEM(node(z0, z1, z2)) -> c6
   APPEND(nil, z0) -> c7
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   LISTIFY(z0, z1) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ISEMPTY(z0))
   LISTIFY(z0, z1) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ISEMPTY(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), RIGHT(z0))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), LEFT(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ELEM(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), RIGHT(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ELEM(z0))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), RIGHT(z0))
   LISTIFY(z0, z1) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), APPEND(z1, z0))
   IF(true, z0, z1, z2, z3, z4) -> c18
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   TOLIST(z0) -> c21(LISTIFY(z0, nil))
K tuples:none
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2, listify_2, if_6, toList_1

Defined Pair Symbols:   ISEMPTY_1, LEFT_1, RIGHT_1, ELEM_1, APPEND_2, LISTIFY_2, IF_6, TOLIST_1

Compound Symbols:   c, c1, c2, c3, c4, c5, c6, c7, c8_1, c9_2, c10_3, c11_2, c12_3, c13_3, c14_3, c15_2, c16_2, c17_2, c18, c19_1, c20_1, c21_1


----------------------------------------

(75) CdtLeafRemovalProof (ComplexityIfPolyImplication)
Removed 1 leading nodes:
   TOLIST(z0) -> c21(LISTIFY(z0, nil))
Removed 9 trailing nodes:
   APPEND(nil, z0) -> c7
   LEFT(node(z0, z1, z2)) -> c3
   IF(true, z0, z1, z2, z3, z4) -> c18
   LEFT(empty) -> c2
   ELEM(node(z0, z1, z2)) -> c6
   ISEMPTY(empty) -> c
   RIGHT(node(z0, z1, z2)) -> c5
   ISEMPTY(node(z0, z1, z2)) -> c1
   RIGHT(empty) -> c4

----------------------------------------

(76)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
   listify(z0, z1) -> if(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))
   if(true, z0, z1, z2, z3, z4) -> z3
   if(false, false, z0, z1, z2, z3) -> listify(z1, z2)
   if(false, true, z0, z1, z2, z3) -> listify(z0, z3)
   toList(z0) -> listify(z0, nil)
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   LISTIFY(z0, z1) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ISEMPTY(z0))
   LISTIFY(z0, z1) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ISEMPTY(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), RIGHT(z0))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), LEFT(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ELEM(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), RIGHT(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ELEM(z0))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), RIGHT(z0))
   LISTIFY(z0, z1) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), APPEND(z1, z0))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   LISTIFY(z0, z1) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ISEMPTY(z0))
   LISTIFY(z0, z1) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ISEMPTY(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), RIGHT(z0))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), LEFT(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ELEM(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), RIGHT(left(z0)), LEFT(z0))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), ELEM(z0))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), RIGHT(z0))
   LISTIFY(z0, z1) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), APPEND(z1, z0))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
K tuples:none
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2, listify_2, if_6, toList_1

Defined Pair Symbols:   APPEND_2, LISTIFY_2, IF_6

Compound Symbols:   c8_1, c9_2, c10_3, c11_2, c12_3, c13_3, c14_3, c15_2, c16_2, c17_2, c19_1, c20_1


----------------------------------------

(77) CdtRhsSimplificationProcessorProof (BOTH BOUNDS(ID, ID))
Removed 12 trailing tuple parts
----------------------------------------

(78)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
   listify(z0, z1) -> if(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))
   if(true, z0, z1, z2, z3, z4) -> z3
   if(false, false, z0, z1, z2, z3) -> listify(z1, z2)
   if(false, true, z0, z1, z2, z3) -> listify(z0, z3)
   toList(z0) -> listify(z0, nil)
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   LISTIFY(z0, z1) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), APPEND(z1, z0))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   LISTIFY(z0, z1) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), APPEND(z1, z0))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
K tuples:none
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2, listify_2, if_6, toList_1

Defined Pair Symbols:   APPEND_2, LISTIFY_2, IF_6

Compound Symbols:   c8_1, c17_2, c19_1, c20_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(79) CdtUsableRulesProof (BOTH BOUNDS(ID, ID))
The following rules are not usable and were removed:
   listify(z0, z1) -> if(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))
   if(true, z0, z1, z2, z3, z4) -> z3
   if(false, false, z0, z1, z2, z3) -> listify(z1, z2)
   if(false, true, z0, z1, z2, z3) -> listify(z0, z3)
   toList(z0) -> listify(z0, nil)

----------------------------------------

(80)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   LISTIFY(z0, z1) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), APPEND(z1, z0))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   LISTIFY(z0, z1) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), APPEND(z1, z0))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
K tuples:none
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, LISTIFY_2, IF_6

Compound Symbols:   c8_1, c17_2, c19_1, c20_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(81) CdtToCpxRelTrsProof (BOTH BOUNDS(ID, ID))
Converted S to standard rules, and D \ S as well as R to relative rules.
----------------------------------------

(82)
Obligation:
The Runtime Complexity (innermost) of the given CpxRelTRS could be proven to be BOUNDS(1, INF).


The TRS R consists of the following rules:

   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   LISTIFY(z0, z1) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), APPEND(z1, z0))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))

The (relative) TRS S consists of the following rules:

   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))

Rewrite Strategy: INNERMOST
----------------------------------------

(83) RelTrsToTrsProof (UPPER BOUND(ID))
transformed relative TRS to TRS
----------------------------------------

(84)
Obligation:
The Runtime Complexity (innermost) of the given CpxTRS could be proven to be BOUNDS(1, INF).


The TRS R consists of the following rules:

   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   LISTIFY(z0, z1) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), APPEND(z1, z0))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))

S is empty.
Rewrite Strategy: INNERMOST
----------------------------------------

(85) RelTrsToWeightedTrsProof (BOTH BOUNDS(ID, ID))
Transformed relative TRS to weighted TRS
----------------------------------------

(86)
Obligation:
The Runtime Complexity (innermost) of the given CpxWeightedTrs could be proven to be BOUNDS(1, INF).


The TRS R consists of the following rules:

   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1)) [1]
   LISTIFY(z0, z1) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), APPEND(z1, z0)) [1]
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2)) [1]
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3)) [1]
   LISTIFY(z0, z1) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) [1]
   LISTIFY(z0, z1) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) [1]
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) [1]
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) [1]
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) [1]
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) [1]
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) [1]
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) [1]
   isEmpty(empty) -> true [0]
   isEmpty(node(z0, z1, z2)) -> false [0]
   left(empty) -> empty [0]
   left(node(z0, z1, z2)) -> z0 [0]
   right(empty) -> empty [0]
   right(node(z0, z1, z2)) -> z2 [0]
   elem(node(z0, z1, z2)) -> z1 [0]
   append(nil, z0) -> cons(z0, nil) [0]
   append(cons(y, z0), z1) -> cons(y, append(z0, z1)) [0]

Rewrite Strategy: INNERMOST
----------------------------------------

(87) TypeInferenceProof (BOTH BOUNDS(ID, ID))
Infered types.
----------------------------------------

(88)
Obligation:
Runtime Complexity Weighted TRS with Types.
The TRS R consists of the following rules:

   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1)) [1]
   LISTIFY(z0, z1) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), APPEND(z1, z0)) [1]
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2)) [1]
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3)) [1]
   LISTIFY(z0, z1) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) [1]
   LISTIFY(z0, z1) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) [1]
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) [1]
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) [1]
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) [1]
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) [1]
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) [1]
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) [1]
   isEmpty(empty) -> true [0]
   isEmpty(node(z0, z1, z2)) -> false [0]
   left(empty) -> empty [0]
   left(node(z0, z1, z2)) -> z0 [0]
   right(empty) -> empty [0]
   right(node(z0, z1, z2)) -> z2 [0]
   elem(node(z0, z1, z2)) -> z1 [0]
   append(nil, z0) -> cons(z0, nil) [0]
   append(cons(y, z0), z1) -> cons(y, append(z0, z1)) [0]

The TRS has the following type information:
APPEND :: cons:nil -> y:node:empty -> c8
cons :: y:node:empty -> cons:nil -> cons:nil
y :: y:node:empty
c8 :: c8 -> c8
LISTIFY :: y:node:empty -> cons:nil -> c17:c9:c10:c11:c12:c13:c14:c15:c16
c17 :: c19:c20 -> c8 -> c17:c9:c10:c11:c12:c13:c14:c15:c16
IF :: false:true -> false:true -> y:node:empty -> y:node:empty -> cons:nil -> cons:nil -> c19:c20
isEmpty :: y:node:empty -> false:true
left :: y:node:empty -> y:node:empty
right :: y:node:empty -> y:node:empty
node :: y:node:empty -> elem -> y:node:empty -> y:node:empty
elem :: y:node:empty -> elem
append :: cons:nil -> y:node:empty -> cons:nil
false :: false:true
c19 :: c17:c9:c10:c11:c12:c13:c14:c15:c16 -> c19:c20
true :: false:true
c20 :: c17:c9:c10:c11:c12:c13:c14:c15:c16 -> c19:c20
c9 :: c19:c20 -> c17:c9:c10:c11:c12:c13:c14:c15:c16
c10 :: c19:c20 -> c17:c9:c10:c11:c12:c13:c14:c15:c16
c11 :: c19:c20 -> c17:c9:c10:c11:c12:c13:c14:c15:c16
c12 :: c19:c20 -> c17:c9:c10:c11:c12:c13:c14:c15:c16
c13 :: c19:c20 -> c17:c9:c10:c11:c12:c13:c14:c15:c16
c14 :: c19:c20 -> c17:c9:c10:c11:c12:c13:c14:c15:c16
c15 :: c19:c20 -> c17:c9:c10:c11:c12:c13:c14:c15:c16
c16 :: c19:c20 -> c17:c9:c10:c11:c12:c13:c14:c15:c16
empty :: y:node:empty
nil :: cons:nil

Rewrite Strategy: INNERMOST
----------------------------------------

(89) CompletionProof (UPPER BOUND(ID))
The transformation into a RNTS is sound, since:

(a) The obligation is a constructor system where every type has a constant constructor,

(b) The following defined symbols do not have to be completely defined, as they can never occur inside other defined symbols:

   APPEND_2
   LISTIFY_2
   IF_6

(c) The following functions are completely defined:

   isEmpty_1
   left_1
   right_1
   elem_1
   append_2

Due to the following rules being added:

   isEmpty(v0) -> null_isEmpty [0]
   left(v0) -> null_left [0]
   right(v0) -> null_right [0]
   elem(v0) -> const3 [0]
   append(v0, v1) -> nil [0]

And the following fresh constants:    null_isEmpty, null_left, null_right, const3, const, const1, const2

----------------------------------------

(90)
Obligation:
Runtime Complexity Weighted TRS where critical functions are completely defined. The underlying TRS is:

Runtime Complexity Weighted TRS with Types.
The TRS R consists of the following rules:

   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1)) [1]
   LISTIFY(z0, z1) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), APPEND(z1, z0)) [1]
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2)) [1]
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3)) [1]
   LISTIFY(z0, z1) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) [1]
   LISTIFY(z0, z1) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) [1]
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) [1]
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) [1]
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) [1]
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) [1]
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) [1]
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) [1]
   isEmpty(empty) -> true [0]
   isEmpty(node(z0, z1, z2)) -> false [0]
   left(empty) -> empty [0]
   left(node(z0, z1, z2)) -> z0 [0]
   right(empty) -> empty [0]
   right(node(z0, z1, z2)) -> z2 [0]
   elem(node(z0, z1, z2)) -> z1 [0]
   append(nil, z0) -> cons(z0, nil) [0]
   append(cons(y, z0), z1) -> cons(y, append(z0, z1)) [0]
   isEmpty(v0) -> null_isEmpty [0]
   left(v0) -> null_left [0]
   right(v0) -> null_right [0]
   elem(v0) -> const3 [0]
   append(v0, v1) -> nil [0]

The TRS has the following type information:
APPEND :: cons:nil -> y:node:empty:null_left:null_right -> c8
cons :: y:node:empty:null_left:null_right -> cons:nil -> cons:nil
y :: y:node:empty:null_left:null_right
c8 :: c8 -> c8
LISTIFY :: y:node:empty:null_left:null_right -> cons:nil -> c17:c9:c10:c11:c12:c13:c14:c15:c16
c17 :: c19:c20 -> c8 -> c17:c9:c10:c11:c12:c13:c14:c15:c16
IF :: false:true:null_isEmpty -> false:true:null_isEmpty -> y:node:empty:null_left:null_right -> y:node:empty:null_left:null_right -> cons:nil -> cons:nil -> c19:c20
isEmpty :: y:node:empty:null_left:null_right -> false:true:null_isEmpty
left :: y:node:empty:null_left:null_right -> y:node:empty:null_left:null_right
right :: y:node:empty:null_left:null_right -> y:node:empty:null_left:null_right
node :: y:node:empty:null_left:null_right -> const3 -> y:node:empty:null_left:null_right -> y:node:empty:null_left:null_right
elem :: y:node:empty:null_left:null_right -> const3
append :: cons:nil -> y:node:empty:null_left:null_right -> cons:nil
false :: false:true:null_isEmpty
c19 :: c17:c9:c10:c11:c12:c13:c14:c15:c16 -> c19:c20
true :: false:true:null_isEmpty
c20 :: c17:c9:c10:c11:c12:c13:c14:c15:c16 -> c19:c20
c9 :: c19:c20 -> c17:c9:c10:c11:c12:c13:c14:c15:c16
c10 :: c19:c20 -> c17:c9:c10:c11:c12:c13:c14:c15:c16
c11 :: c19:c20 -> c17:c9:c10:c11:c12:c13:c14:c15:c16
c12 :: c19:c20 -> c17:c9:c10:c11:c12:c13:c14:c15:c16
c13 :: c19:c20 -> c17:c9:c10:c11:c12:c13:c14:c15:c16
c14 :: c19:c20 -> c17:c9:c10:c11:c12:c13:c14:c15:c16
c15 :: c19:c20 -> c17:c9:c10:c11:c12:c13:c14:c15:c16
c16 :: c19:c20 -> c17:c9:c10:c11:c12:c13:c14:c15:c16
empty :: y:node:empty:null_left:null_right
nil :: cons:nil
null_isEmpty :: false:true:null_isEmpty
null_left :: y:node:empty:null_left:null_right
null_right :: y:node:empty:null_left:null_right
const3 :: const3
const :: c8
const1 :: c17:c9:c10:c11:c12:c13:c14:c15:c16
const2 :: c19:c20

Rewrite Strategy: INNERMOST
----------------------------------------

(91) CompletionProof (UPPER BOUND(ID))
The TRS is a completely defined constructor system, as every type has a constant constructor and the following rules were added:

   isEmpty(v0) -> null_isEmpty [0]
   left(v0) -> null_left [0]
   right(v0) -> null_right [0]
   elem(v0) -> null_elem [0]
   append(v0, v1) -> null_append [0]
   APPEND(v0, v1) -> null_APPEND [0]
   IF(v0, v1, v2, v3, v4, v5) -> null_IF [0]

And the following fresh constants:    null_isEmpty, null_left, null_right, null_elem, null_append, null_APPEND, null_IF, const

----------------------------------------

(92)
Obligation:
Runtime Complexity Weighted TRS where all functions are completely defined. The underlying TRS is:

Runtime Complexity Weighted TRS with Types.
The TRS R consists of the following rules:

   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1)) [1]
   LISTIFY(z0, z1) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), APPEND(z1, z0)) [1]
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2)) [1]
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3)) [1]
   LISTIFY(z0, z1) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) [1]
   LISTIFY(z0, z1) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) [1]
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) [1]
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) [1]
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) [1]
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) [1]
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) [1]
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) [1]
   isEmpty(empty) -> true [0]
   isEmpty(node(z0, z1, z2)) -> false [0]
   left(empty) -> empty [0]
   left(node(z0, z1, z2)) -> z0 [0]
   right(empty) -> empty [0]
   right(node(z0, z1, z2)) -> z2 [0]
   elem(node(z0, z1, z2)) -> z1 [0]
   append(nil, z0) -> cons(z0, nil) [0]
   append(cons(y, z0), z1) -> cons(y, append(z0, z1)) [0]
   isEmpty(v0) -> null_isEmpty [0]
   left(v0) -> null_left [0]
   right(v0) -> null_right [0]
   elem(v0) -> null_elem [0]
   append(v0, v1) -> null_append [0]
   APPEND(v0, v1) -> null_APPEND [0]
   IF(v0, v1, v2, v3, v4, v5) -> null_IF [0]

The TRS has the following type information:
APPEND :: cons:nil:null_append -> y:node:empty:null_left:null_right -> c8:null_APPEND
cons :: y:node:empty:null_left:null_right -> cons:nil:null_append -> cons:nil:null_append
y :: y:node:empty:null_left:null_right
c8 :: c8:null_APPEND -> c8:null_APPEND
LISTIFY :: y:node:empty:null_left:null_right -> cons:nil:null_append -> c17:c9:c10:c11:c12:c13:c14:c15:c16
c17 :: c19:c20:null_IF -> c8:null_APPEND -> c17:c9:c10:c11:c12:c13:c14:c15:c16
IF :: false:true:null_isEmpty -> false:true:null_isEmpty -> y:node:empty:null_left:null_right -> y:node:empty:null_left:null_right -> cons:nil:null_append -> cons:nil:null_append -> c19:c20:null_IF
isEmpty :: y:node:empty:null_left:null_right -> false:true:null_isEmpty
left :: y:node:empty:null_left:null_right -> y:node:empty:null_left:null_right
right :: y:node:empty:null_left:null_right -> y:node:empty:null_left:null_right
node :: y:node:empty:null_left:null_right -> null_elem -> y:node:empty:null_left:null_right -> y:node:empty:null_left:null_right
elem :: y:node:empty:null_left:null_right -> null_elem
append :: cons:nil:null_append -> y:node:empty:null_left:null_right -> cons:nil:null_append
false :: false:true:null_isEmpty
c19 :: c17:c9:c10:c11:c12:c13:c14:c15:c16 -> c19:c20:null_IF
true :: false:true:null_isEmpty
c20 :: c17:c9:c10:c11:c12:c13:c14:c15:c16 -> c19:c20:null_IF
c9 :: c19:c20:null_IF -> c17:c9:c10:c11:c12:c13:c14:c15:c16
c10 :: c19:c20:null_IF -> c17:c9:c10:c11:c12:c13:c14:c15:c16
c11 :: c19:c20:null_IF -> c17:c9:c10:c11:c12:c13:c14:c15:c16
c12 :: c19:c20:null_IF -> c17:c9:c10:c11:c12:c13:c14:c15:c16
c13 :: c19:c20:null_IF -> c17:c9:c10:c11:c12:c13:c14:c15:c16
c14 :: c19:c20:null_IF -> c17:c9:c10:c11:c12:c13:c14:c15:c16
c15 :: c19:c20:null_IF -> c17:c9:c10:c11:c12:c13:c14:c15:c16
c16 :: c19:c20:null_IF -> c17:c9:c10:c11:c12:c13:c14:c15:c16
empty :: y:node:empty:null_left:null_right
nil :: cons:nil:null_append
null_isEmpty :: false:true:null_isEmpty
null_left :: y:node:empty:null_left:null_right
null_right :: y:node:empty:null_left:null_right
null_elem :: null_elem
null_append :: cons:nil:null_append
null_APPEND :: c8:null_APPEND
null_IF :: c19:c20:null_IF
const :: c17:c9:c10:c11:c12:c13:c14:c15:c16

Rewrite Strategy: INNERMOST
----------------------------------------

(93) CpxTypedWeightedTrsToRntsProof (UPPER BOUND(ID))
Transformed the TRS into an over-approximating RNTS by (improved) Size Abstraction.
The constant constructors are abstracted as follows:

   y => 1
   false => 1
   true => 2
   empty => 0
   nil => 0
   null_isEmpty => 0
   null_left => 0
   null_right => 0
   null_elem => 0
   null_append => 0
   null_APPEND => 0
   null_IF => 0
   const => 0

----------------------------------------

(94)
Obligation:
Complexity RNTS consisting of the following rules:

   APPEND(z, z') -{ 0 }-> 0 :|: v0 >= 0, v1 >= 0, z = v0, z' = v1
   APPEND(z, z') -{ 1 }-> 1 + APPEND(z0, z1) :|: z1 >= 0, z' = z1, z0 >= 0, z = 1 + 1 + z0
   IF(z, z', z'', z4, z5, z6) -{ 0 }-> 0 :|: z5 = v4, v0 >= 0, v4 >= 0, z6 = v5, z'' = v2, v1 >= 0, v5 >= 0, z = v0, z' = v1, z4 = v3, v2 >= 0, v3 >= 0
   IF(z, z', z'', z4, z5, z6) -{ 1 }-> 1 + LISTIFY(z0, z3) :|: z1 >= 0, z' = 2, z = 1, z6 = z3, z'' = z0, z0 >= 0, z4 = z1, z5 = z2, z2 >= 0, z3 >= 0
   IF(z, z', z'', z4, z5, z6) -{ 1 }-> 1 + LISTIFY(z1, z2) :|: z1 >= 0, z = 1, z6 = z3, z'' = z0, z0 >= 0, z' = 1, z4 = z1, z5 = z2, z2 >= 0, z3 >= 0
   LISTIFY(z, z') -{ 1 }-> 1 + IF(isEmpty(z0), isEmpty(left(z0)), right(z0), 1 + left(left(z0)) + elem(left(z0)) + (1 + right(left(z0)) + elem(z0) + right(z0)), z1, append(z1, z0)) :|: z = z0, z1 >= 0, z' = z1, z0 >= 0
   LISTIFY(z, z') -{ 1 }-> 1 + IF(isEmpty(z0), isEmpty(left(z0)), right(z0), 1 + left(left(z0)) + elem(left(z0)) + (1 + right(left(z0)) + elem(z0) + right(z0)), z1, append(z1, z0)) + APPEND(z1, z0) :|: z = z0, z1 >= 0, z' = z1, z0 >= 0
   append(z, z') -{ 0 }-> 0 :|: v0 >= 0, v1 >= 0, z = v0, z' = v1
   append(z, z') -{ 0 }-> 1 + z0 + 0 :|: z0 >= 0, z = 0, z' = z0
   append(z, z') -{ 0 }-> 1 + 1 + append(z0, z1) :|: z1 >= 0, z' = z1, z0 >= 0, z = 1 + 1 + z0
   elem(z) -{ 0 }-> z1 :|: z1 >= 0, z = 1 + z0 + z1 + z2, z0 >= 0, z2 >= 0
   elem(z) -{ 0 }-> 0 :|: v0 >= 0, z = v0
   isEmpty(z) -{ 0 }-> 2 :|: z = 0
   isEmpty(z) -{ 0 }-> 1 :|: z1 >= 0, z = 1 + z0 + z1 + z2, z0 >= 0, z2 >= 0
   isEmpty(z) -{ 0 }-> 0 :|: v0 >= 0, z = v0
   left(z) -{ 0 }-> z0 :|: z1 >= 0, z = 1 + z0 + z1 + z2, z0 >= 0, z2 >= 0
   left(z) -{ 0 }-> 0 :|: z = 0
   left(z) -{ 0 }-> 0 :|: v0 >= 0, z = v0
   right(z) -{ 0 }-> z2 :|: z1 >= 0, z = 1 + z0 + z1 + z2, z0 >= 0, z2 >= 0
   right(z) -{ 0 }-> 0 :|: z = 0
   right(z) -{ 0 }-> 0 :|: v0 >= 0, z = v0

Only complete derivations are relevant for the runtime complexity.

----------------------------------------

(95) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(z0, z1) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)), APPEND(z1, z0)) by 
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)), APPEND(nil, z0))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))

----------------------------------------

(96)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)), APPEND(nil, z0))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)), APPEND(nil, z0))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
K tuples:none
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2


----------------------------------------

(97) CdtRhsSimplificationProcessorProof (BOTH BOUNDS(ID, ID))
Removed 2 trailing tuple parts
----------------------------------------

(98)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
K tuples:none
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2, c17_1


----------------------------------------

(99) CdtRuleRemovalProof (UPPER BOUND(ADD(n^1)))
Found a reduction pair which oriented the following tuples strictly. Hence they can be removed from S.
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
We considered the (Usable) Rules:none
And the Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
The order we found is given by the following interpretation:

Polynomial interpretation :

   POL(APPEND(x_1, x_2)) = 0
   POL(IF(x_1, x_2, x_3, x_4, x_5, x_6)) = [1]
   POL(LISTIFY(x_1, x_2)) = [1]
   POL(append(x_1, x_2)) = x_1 + x_2
   POL(c10(x_1)) = x_1
   POL(c11(x_1)) = x_1
   POL(c12(x_1)) = x_1
   POL(c13(x_1)) = x_1
   POL(c14(x_1)) = x_1
   POL(c15(x_1)) = x_1
   POL(c16(x_1)) = x_1
   POL(c17(x_1)) = x_1
   POL(c17(x_1, x_2)) = x_1 + x_2
   POL(c19(x_1)) = x_1
   POL(c20(x_1)) = x_1
   POL(c8(x_1)) = x_1
   POL(c9(x_1)) = x_1
   POL(cons(x_1, x_2)) = 0
   POL(elem(x_1)) = [1]
   POL(empty) = 0
   POL(false) = [1]
   POL(isEmpty(x_1)) = [1]
   POL(left(x_1)) = [1]
   POL(nil) = 0
   POL(node(x_1, x_2, x_3)) = 0
   POL(right(x_1)) = [1]
   POL(true) = [1]
   POL(y) = 0

----------------------------------------

(100)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2, c17_1


----------------------------------------

(101) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(z0, z1) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) by 
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))

----------------------------------------

(102)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2, c17_1, c9_1


----------------------------------------

(103) CdtLeafRemovalProof (BOTH BOUNDS(ID, ID))
Removed 1 trailing nodes:
   LISTIFY(empty, x1) -> c9(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))

----------------------------------------

(104)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2, c17_1, c9_1


----------------------------------------

(105) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(z0, z1) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) by 
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))

----------------------------------------

(106)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2, c17_1, c9_1, c10_1


----------------------------------------

(107) CdtLeafRemovalProof (BOTH BOUNDS(ID, ID))
Removed 1 trailing nodes:
   LISTIFY(empty, x1) -> c10(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))

----------------------------------------

(108)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2, c17_1, c9_1, c10_1


----------------------------------------

(109) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(z0, z1) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) by 
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))

----------------------------------------

(110)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2, c17_1, c9_1, c10_1, c11_1


----------------------------------------

(111) CdtLeafRemovalProof (BOTH BOUNDS(ID, ID))
Removed 1 trailing nodes:
   LISTIFY(empty, x1) -> c11(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))

----------------------------------------

(112)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2, c17_1, c9_1, c10_1, c11_1


----------------------------------------

(113) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(z0, z1) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) by 
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))

----------------------------------------

(114)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c13_1, c14_1, c15_1, c16_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1


----------------------------------------

(115) CdtLeafRemovalProof (BOTH BOUNDS(ID, ID))
Removed 1 trailing nodes:
   LISTIFY(empty, x1) -> c12(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))

----------------------------------------

(116)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c13_1, c14_1, c15_1, c16_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1


----------------------------------------

(117) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(z0, z1) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) by 
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))

----------------------------------------

(118)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c14_1, c15_1, c16_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1


----------------------------------------

(119) CdtLeafRemovalProof (BOTH BOUNDS(ID, ID))
Removed 1 trailing nodes:
   LISTIFY(empty, x1) -> c13(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))

----------------------------------------

(120)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c14_1, c15_1, c16_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1


----------------------------------------

(121) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(z0, z1) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) by 
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))

----------------------------------------

(122)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c15_1, c16_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1


----------------------------------------

(123) CdtLeafRemovalProof (BOTH BOUNDS(ID, ID))
Removed 1 trailing nodes:
   LISTIFY(empty, x1) -> c14(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))

----------------------------------------

(124)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c15_1, c16_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1


----------------------------------------

(125) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(z0, z1) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) by 
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))

----------------------------------------

(126)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c16_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1


----------------------------------------

(127) CdtLeafRemovalProof (BOTH BOUNDS(ID, ID))
Removed 1 trailing nodes:
   LISTIFY(empty, x1) -> c15(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))

----------------------------------------

(128)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0)))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c16_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1


----------------------------------------

(129) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(z0, z1) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), z1, append(z1, z0))) by 
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))

----------------------------------------

(130)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(131) CdtLeafRemovalProof (BOTH BOUNDS(ID, ID))
Removed 1 trailing nodes:
   LISTIFY(empty, x1) -> c16(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))

----------------------------------------

(132)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(133) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(z1, cons(y, z0)) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))), APPEND(cons(y, z0), z1)) by 
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))

----------------------------------------

(134)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(135) CdtRhsSimplificationProcessorProof (BOTH BOUNDS(ID, ID))
Removed 1 trailing tuple parts
----------------------------------------

(136)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


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(137) CdtRuleRemovalProof (UPPER BOUND(ADD(n^1)))
Found a reduction pair which oriented the following tuples strictly. Hence they can be removed from S.
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
We considered the (Usable) Rules:none
And the Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
The order we found is given by the following interpretation:

Polynomial interpretation :

   POL(APPEND(x_1, x_2)) = 0
   POL(IF(x_1, x_2, x_3, x_4, x_5, x_6)) = [1]
   POL(LISTIFY(x_1, x_2)) = [1]
   POL(append(x_1, x_2)) = x_1 + x_2
   POL(c10(x_1)) = x_1
   POL(c11(x_1)) = x_1
   POL(c12(x_1)) = x_1
   POL(c13(x_1)) = x_1
   POL(c14(x_1)) = x_1
   POL(c15(x_1)) = x_1
   POL(c16(x_1)) = x_1
   POL(c17(x_1)) = x_1
   POL(c17(x_1, x_2)) = x_1 + x_2
   POL(c19(x_1)) = x_1
   POL(c20(x_1)) = x_1
   POL(c8(x_1)) = x_1
   POL(c9(x_1)) = x_1
   POL(cons(x_1, x_2)) = 0
   POL(elem(x_1)) = [1]
   POL(empty) = 0
   POL(false) = [1]
   POL(isEmpty(x_1)) = [1]
   POL(left(x_1)) = 0
   POL(nil) = 0
   POL(node(x_1, x_2, x_3)) = 0
   POL(right(x_1)) = [1]
   POL(true) = [1]
   POL(y) = 0

----------------------------------------

(138)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(139) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)), APPEND(x1, empty)) by 
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)), APPEND(nil, empty))
   LISTIFY(empty, cons(y, z0)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, z0), cons(y, append(z0, empty))), APPEND(cons(y, z0), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))

----------------------------------------

(140)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)), APPEND(nil, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)), APPEND(nil, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(141) CdtRhsSimplificationProcessorProof (BOTH BOUNDS(ID, ID))
Removed 2 trailing tuple parts
----------------------------------------

(142)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(empty, x0) -> c17(APPEND(x0, empty))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(143) CdtKnowledgeProof (BOTH BOUNDS(ID, ID))
The following tuples could be moved from S to K by knowledge propagation:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(empty, x0) -> c17(APPEND(x0, empty))

----------------------------------------

(144)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


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(145) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2))) by 
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)), APPEND(nil, node(x0, x1, x2)))
   LISTIFY(node(x0, x1, x2), cons(y, z0)) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), cons(y, z0), cons(y, append(z0, node(x0, x1, x2)))), APPEND(cons(y, z0), node(x0, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))

----------------------------------------

(146)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)), APPEND(nil, node(x0, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)), APPEND(nil, node(x0, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(147) CdtRhsSimplificationProcessorProof (BOTH BOUNDS(ID, ID))
Removed 1 trailing tuple parts
----------------------------------------

(148)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(149) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2))) by 
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)), APPEND(nil, node(x0, x1, x2)))
   LISTIFY(node(x0, x1, x2), cons(y, z0)) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), cons(y, z0), cons(y, append(z0, node(x0, x1, x2)))), APPEND(cons(y, z0), node(x0, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))

----------------------------------------

(150)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)), APPEND(nil, node(x0, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)), APPEND(nil, node(x0, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(151) CdtRhsSimplificationProcessorProof (BOTH BOUNDS(ID, ID))
Removed 1 trailing tuple parts
----------------------------------------

(152)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(153) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty)) by 
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)), APPEND(nil, empty))
   LISTIFY(empty, cons(y, z0)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, z0), cons(y, append(z0, empty))), APPEND(cons(y, z0), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))

----------------------------------------

(154)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)), APPEND(nil, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)), APPEND(nil, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(155) CdtRhsSimplificationProcessorProof (BOTH BOUNDS(ID, ID))
Removed 2 trailing tuple parts
----------------------------------------

(156)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(empty, x0) -> c17(APPEND(x0, empty))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(157) CdtKnowledgeProof (BOTH BOUNDS(ID, ID))
The following tuples could be moved from S to K by knowledge propagation:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(empty, x0) -> c17(APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(APPEND(x0, empty))

----------------------------------------

(158)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(159) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2))) by 
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)), APPEND(nil, node(x0, x1, x2)))
   LISTIFY(node(x0, x1, x2), cons(y, z0)) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), cons(y, z0), cons(y, append(z0, node(x0, x1, x2)))), APPEND(cons(y, z0), node(x0, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))

----------------------------------------

(160)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)), APPEND(nil, node(x0, x1, x2)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)), APPEND(nil, node(x0, x1, x2)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(161) CdtRhsSimplificationProcessorProof (BOTH BOUNDS(ID, ID))
Removed 1 trailing tuple parts
----------------------------------------

(162)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(163) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty)) by 
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)), APPEND(nil, empty))
   LISTIFY(empty, cons(y, z0)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, z0), cons(y, append(z0, empty))), APPEND(cons(y, z0), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))

----------------------------------------

(164)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)), APPEND(nil, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)), APPEND(nil, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(165) CdtRhsSimplificationProcessorProof (BOTH BOUNDS(ID, ID))
Removed 2 trailing tuple parts
----------------------------------------

(166)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(empty, x0) -> c17(APPEND(x0, empty))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(167) CdtKnowledgeProof (BOTH BOUNDS(ID, ID))
The following tuples could be moved from S to K by knowledge propagation:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(empty, x0) -> c17(APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(APPEND(x0, empty))

----------------------------------------

(168)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(169) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2))) by 
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)), APPEND(nil, node(x0, x1, x2)))
   LISTIFY(node(x0, x1, x2), cons(y, z0)) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), cons(y, z0), cons(y, append(z0, node(x0, x1, x2)))), APPEND(cons(y, z0), node(x0, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))

----------------------------------------

(170)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)), APPEND(nil, node(x0, x1, x2)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)), APPEND(nil, node(x0, x1, x2)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(171) CdtRhsSimplificationProcessorProof (BOTH BOUNDS(ID, ID))
Removed 1 trailing tuple parts
----------------------------------------

(172)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(173) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty)) by 
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)), APPEND(nil, empty))
   LISTIFY(empty, cons(y, z0)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, z0), cons(y, append(z0, empty))), APPEND(cons(y, z0), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(true, isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))

----------------------------------------

(174)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)), APPEND(nil, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(true, isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)), APPEND(nil, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(true, isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(175) CdtRhsSimplificationProcessorProof (BOTH BOUNDS(ID, ID))
Removed 2 trailing tuple parts
----------------------------------------

(176)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(empty, x0) -> c17(APPEND(x0, empty))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(177) CdtKnowledgeProof (BOTH BOUNDS(ID, ID))
The following tuples could be moved from S to K by knowledge propagation:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(empty, x0) -> c17(APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(APPEND(x0, empty))

----------------------------------------

(178)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(179) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2))) by 
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)), APPEND(nil, node(x0, x1, x2)))
   LISTIFY(node(x0, x1, x2), cons(y, z0)) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), cons(y, z0), cons(y, append(z0, node(x0, x1, x2)))), APPEND(cons(y, z0), node(x0, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))

----------------------------------------

(180)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)), APPEND(nil, node(x0, x1, x2)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)), APPEND(nil, node(x0, x1, x2)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(181) CdtRhsSimplificationProcessorProof (BOTH BOUNDS(ID, ID))
Removed 1 trailing tuple parts
----------------------------------------

(182)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(183) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty)) by 
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)), APPEND(nil, empty))
   LISTIFY(empty, cons(y, z0)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, z0), cons(y, append(z0, empty))), APPEND(cons(y, z0), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(true, isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))

----------------------------------------

(184)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)), APPEND(nil, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(true, isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)), APPEND(nil, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(true, isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(185) CdtRhsSimplificationProcessorProof (BOTH BOUNDS(ID, ID))
Removed 2 trailing tuple parts
----------------------------------------

(186)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(empty, x0) -> c17(APPEND(x0, empty))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(187) CdtKnowledgeProof (BOTH BOUNDS(ID, ID))
The following tuples could be moved from S to K by knowledge propagation:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(empty, x0) -> c17(APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(APPEND(x0, empty))

----------------------------------------

(188)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(189) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2))) by 
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)), APPEND(nil, node(x0, x1, x2)))
   LISTIFY(node(x0, x1, x2), cons(y, z0)) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), cons(y, z0), cons(y, append(z0, node(x0, x1, x2)))), APPEND(cons(y, z0), node(x0, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))

----------------------------------------

(190)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)), APPEND(nil, node(x0, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)), APPEND(nil, node(x0, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(191) CdtRhsSimplificationProcessorProof (BOTH BOUNDS(ID, ID))
Removed 1 trailing tuple parts
----------------------------------------

(192)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(193) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(empty, x1) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)), APPEND(x1, empty)) by 
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)), APPEND(nil, empty))
   LISTIFY(empty, cons(y, z0)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, z0), cons(y, append(z0, empty))), APPEND(cons(y, z0), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(true, isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))

----------------------------------------

(194)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)), APPEND(nil, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(true, isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)), APPEND(nil, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(true, isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(195) CdtRhsSimplificationProcessorProof (BOTH BOUNDS(ID, ID))
Removed 2 trailing tuple parts
----------------------------------------

(196)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(empty, x0) -> c17(APPEND(x0, empty))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(197) CdtKnowledgeProof (BOTH BOUNDS(ID, ID))
The following tuples could be moved from S to K by knowledge propagation:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(empty, x0) -> c17(APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(APPEND(x0, empty))

----------------------------------------

(198)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(199) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(node(z0, z1, z2), x1) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2))) by 
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)), APPEND(nil, node(x0, x1, x2)))
   LISTIFY(node(x0, x1, x2), cons(y, z0)) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), cons(y, z0), cons(y, append(z0, node(x0, x1, x2)))), APPEND(cons(y, z0), node(x0, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))

----------------------------------------

(200)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)), APPEND(nil, node(x0, x1, x2)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)), APPEND(nil, node(x0, x1, x2)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(201) CdtRhsSimplificationProcessorProof (BOTH BOUNDS(ID, ID))
Removed 1 trailing tuple parts
----------------------------------------

(202)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2)))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_2, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1


----------------------------------------

(203) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(node(z0, z1, z2), x1) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))), APPEND(x1, node(z0, z1, z2))) by 
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)), APPEND(nil, node(x0, x1, x2)))
   LISTIFY(node(x0, x1, x2), cons(y, z0)) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), cons(y, z0), cons(y, append(z0, node(x0, x1, x2)))), APPEND(cons(y, z0), node(x0, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))

----------------------------------------

(204)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)), APPEND(nil, node(x0, x1, x2)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)), APPEND(nil, node(x0, x1, x2)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2


----------------------------------------

(205) CdtRhsSimplificationProcessorProof (BOTH BOUNDS(ID, ID))
Removed 1 trailing tuple parts
----------------------------------------

(206)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2


----------------------------------------

(207) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(z0, nil) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil))) by 
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c17(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))

----------------------------------------

(208)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c17(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c17(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2


----------------------------------------

(209) CdtLeafRemovalProof (BOTH BOUNDS(ID, ID))
Removed 1 trailing nodes:
   LISTIFY(empty, nil) -> c17(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))

----------------------------------------

(210)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2


----------------------------------------

(211) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(z0, nil) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil))) by 
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))

----------------------------------------

(212)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2


----------------------------------------

(213) CdtLeafRemovalProof (BOTH BOUNDS(ID, ID))
Removed 1 trailing nodes:
   LISTIFY(empty, nil) -> c9(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))

----------------------------------------

(214)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2


----------------------------------------

(215) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(z1, cons(y, z0)) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1)))) by 
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))

----------------------------------------

(216)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2


----------------------------------------

(217) CdtLeafRemovalProof (BOTH BOUNDS(ID, ID))
Removed 1 trailing nodes:
   LISTIFY(empty, cons(y, x1)) -> c9(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))

----------------------------------------

(218)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2


----------------------------------------

(219) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty))) by 
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(empty, cons(y, z0)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, z0), cons(y, append(z0, empty))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))

----------------------------------------

(220)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2


----------------------------------------

(221) CdtLeafRemovalProof (BOTH BOUNDS(ID, ID))
Removed 1 trailing nodes:
   LISTIFY(empty, x0) -> c9(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))

----------------------------------------

(222)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2


----------------------------------------

(223) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2)))) by 
   LISTIFY(node(x0, x1, x2), nil) -> c9(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), cons(y, z0)) -> c9(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), cons(y, z0), cons(y, append(z0, node(x0, x1, x2)))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))

----------------------------------------

(224)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2


----------------------------------------

(225) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2)))) by 
   LISTIFY(node(x0, x1, x2), nil) -> c9(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), cons(y, z0)) -> c9(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), cons(y, z0), cons(y, append(z0, node(x0, x1, x2)))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))

----------------------------------------

(226)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2


----------------------------------------

(227) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty))) by 
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(empty, cons(y, z0)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, z0), cons(y, append(z0, empty))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))

----------------------------------------

(228)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2


----------------------------------------

(229) CdtLeafRemovalProof (BOTH BOUNDS(ID, ID))
Removed 1 trailing nodes:
   LISTIFY(empty, x0) -> c9(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))

----------------------------------------

(230)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2


----------------------------------------

(231) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2)))) by 
   LISTIFY(node(x0, x1, x2), nil) -> c9(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), cons(y, z0)) -> c9(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), cons(y, z0), cons(y, append(z0, node(x0, x1, x2)))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))

----------------------------------------

(232)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2


----------------------------------------

(233) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty))) by 
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(empty, cons(y, z0)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, z0), cons(y, append(z0, empty))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))

----------------------------------------

(234)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2


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(235) CdtLeafRemovalProof (BOTH BOUNDS(ID, ID))
Removed 1 trailing nodes:
   LISTIFY(empty, x0) -> c9(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))

----------------------------------------

(236)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2


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(237) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2)))) by 
   LISTIFY(node(x0, x1, x2), nil) -> c9(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), cons(y, z0)) -> c9(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), cons(y, z0), cons(y, append(z0, node(x0, x1, x2)))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))

----------------------------------------

(238)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2


----------------------------------------

(239) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty))) by 
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(empty, cons(y, z0)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, z0), cons(y, append(z0, empty))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(true, isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))

----------------------------------------

(240)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(true, isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(true, isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2


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(241) CdtLeafRemovalProof (BOTH BOUNDS(ID, ID))
Removed 1 trailing nodes:
   LISTIFY(empty, x0) -> c9(IF(true, isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))

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(242)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2


----------------------------------------

(243) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2)))) by 
   LISTIFY(node(x0, x1, x2), nil) -> c9(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), cons(y, z0)) -> c9(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), cons(y, z0), cons(y, append(z0, node(x0, x1, x2)))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))

----------------------------------------

(244)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2


----------------------------------------

(245) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty))) by 
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(empty, cons(y, z0)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, z0), cons(y, append(z0, empty))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(true, isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))

----------------------------------------

(246)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(true, isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(true, isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2


----------------------------------------

(247) CdtLeafRemovalProof (BOTH BOUNDS(ID, ID))
Removed 1 trailing nodes:
   LISTIFY(empty, x0) -> c9(IF(true, isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))

----------------------------------------

(248)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2


----------------------------------------

(249) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2)))) by 
   LISTIFY(node(x0, x1, x2), nil) -> c9(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), cons(y, z0)) -> c9(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), cons(y, z0), cons(y, append(z0, node(x0, x1, x2)))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))

----------------------------------------

(250)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2


----------------------------------------

(251) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(empty, x1) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty))) by 
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(empty, cons(y, z0)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, z0), cons(y, append(z0, empty))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(true, isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))

----------------------------------------

(252)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(true, isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(true, isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2


----------------------------------------

(253) CdtLeafRemovalProof (BOTH BOUNDS(ID, ID))
Removed 1 trailing nodes:
   LISTIFY(empty, x0) -> c9(IF(true, isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))

----------------------------------------

(254)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2


----------------------------------------

(255) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(node(z0, z1, z2), x1) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2)))) by 
   LISTIFY(node(x0, x1, x2), nil) -> c9(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), cons(y, z0)) -> c9(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), cons(y, z0), cons(y, append(z0, node(x0, x1, x2)))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))

----------------------------------------

(256)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_1, c9_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2


----------------------------------------

(257) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(node(z0, z1, z2), x1) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2)))) by 
   LISTIFY(node(x0, x1, x2), nil) -> c9(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), cons(y, z0)) -> c9(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), cons(y, z0), cons(y, append(z0, node(x0, x1, x2)))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))

----------------------------------------

(258)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2, c9_1


----------------------------------------

(259) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(z0, nil) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil))) by 
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))

----------------------------------------

(260)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2, c9_1


----------------------------------------

(261) CdtLeafRemovalProof (BOTH BOUNDS(ID, ID))
Removed 1 trailing nodes:
   LISTIFY(empty, nil) -> c10(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))

----------------------------------------

(262)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2, c9_1


----------------------------------------

(263) CdtNarrowingProof (BOTH BOUNDS(ID, ID))
Use narrowing to replace LISTIFY(z1, cons(y, z0)) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1)))) by 
   LISTIFY(z0, cons(y, nil)) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c10(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))

----------------------------------------

(264)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c10(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c10(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2, c9_1


----------------------------------------

(265) CdtLeafRemovalProof (BOTH BOUNDS(ID, ID))
Removed 1 trailing nodes:
   LISTIFY(empty, cons(y, x1)) -> c10(IF(true, isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))

----------------------------------------

(266)
Obligation:
Complexity Dependency Tuples Problem

Rules:
   isEmpty(empty) -> true
   isEmpty(node(z0, z1, z2)) -> false
   left(empty) -> empty
   left(node(z0, z1, z2)) -> z0
   right(empty) -> empty
   right(node(z0, z1, z2)) -> z2
   elem(node(z0, z1, z2)) -> z1
   append(nil, z0) -> cons(z0, nil)
   append(cons(y, z0), z1) -> cons(y, append(z0, z1))
Tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
S tuples:
   APPEND(cons(y, z0), z1) -> c8(APPEND(z0, z1))
   IF(false, false, z0, z1, z2, z3) -> c19(LISTIFY(z1, z2))
   IF(false, true, z0, z1, z2, z3) -> c20(LISTIFY(z0, z3))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c11(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c11(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c11(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c11(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c12(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c12(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c12(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c12(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c13(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c13(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c13(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c13(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c14(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c14(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c14(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c14(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c15(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c15(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c15(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c15(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, nil) -> c16(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), nil, cons(z0, nil)))
   LISTIFY(z1, cons(y, z0)) -> c16(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, z0), cons(y, append(z0, z1))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(empty, x1) -> c16(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x1, append(x1, empty)))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x1) -> c16(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x1, append(x1, node(z0, z1, z2))))
   LISTIFY(z0, cons(y, nil)) -> c17(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))), APPEND(cons(y, nil), z0))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c17(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))), APPEND(cons(y, cons(y, z0)), z1))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, cons(y, x1)) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))), APPEND(cons(y, x1), empty))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))), APPEND(cons(y, x1), node(z0, z1, z2)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), x2)), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), x1, right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(x0), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(x0), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(x0), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(left(node(x0, x1, x2))), x2, node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, x0) -> c17(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)), APPEND(x0, empty))
   LISTIFY(empty, nil) -> c17(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c17(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))), APPEND(x3, node(node(z0, z1, z2), x1, x2)))
   LISTIFY(node(empty, x1, x2), x3) -> c17(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))), APPEND(x3, node(empty, x1, x2)))
   LISTIFY(node(z0, z1, z2), x3) -> c17(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))), APPEND(x3, node(z0, z1, z2)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(isEmpty(node(x0, x1, x2)), isEmpty(x0), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(node(x0, x1, x2), nil) -> c17(IF(false, isEmpty(left(node(x0, x1, x2))), right(node(x0, x1, x2)), node(left(left(node(x0, x1, x2))), elem(left(node(x0, x1, x2))), node(right(left(node(x0, x1, x2))), elem(node(x0, x1, x2)), right(node(x0, x1, x2)))), nil, cons(node(x0, x1, x2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c9(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c9(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(empty, elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(z2, elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(empty, elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), z1, node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(empty, elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), isEmpty(left(node(node(z0, z1, z2), x1, x2))), right(node(node(z0, z1, z2), x1, x2)), node(z0, elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), isEmpty(left(node(empty, x1, x2))), right(node(empty, x1, x2)), node(empty, elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), isEmpty(empty), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, x0) -> c9(IF(isEmpty(empty), true, right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), x0, append(x0, empty)))
   LISTIFY(node(node(z0, z1, z2), x1, x2), x3) -> c9(IF(isEmpty(node(node(z0, z1, z2), x1, x2)), false, right(node(node(z0, z1, z2), x1, x2)), node(left(left(node(node(z0, z1, z2), x1, x2))), elem(left(node(node(z0, z1, z2), x1, x2))), node(right(left(node(node(z0, z1, z2), x1, x2))), elem(node(node(z0, z1, z2), x1, x2)), right(node(node(z0, z1, z2), x1, x2)))), x3, append(x3, node(node(z0, z1, z2), x1, x2))))
   LISTIFY(node(empty, x1, x2), x3) -> c9(IF(isEmpty(node(empty, x1, x2)), true, right(node(empty, x1, x2)), node(left(left(node(empty, x1, x2))), elem(left(node(empty, x1, x2))), node(right(left(node(empty, x1, x2))), elem(node(empty, x1, x2)), right(node(empty, x1, x2)))), x3, append(x3, node(empty, x1, x2))))
   LISTIFY(node(z0, z1, z2), x3) -> c9(IF(false, isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), x3, append(x3, node(z0, z1, z2))))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(empty, nil) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), nil, cons(empty, nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(node(z0, z1, z2), nil) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), nil, cons(node(z0, z1, z2), nil)))
   LISTIFY(z0, cons(y, nil)) -> c10(IF(isEmpty(z0), isEmpty(left(z0)), right(z0), node(left(left(z0)), elem(left(z0)), node(right(left(z0)), elem(z0), right(z0))), cons(y, nil), cons(y, cons(z0, nil))))
   LISTIFY(z1, cons(y, cons(y, z0))) -> c10(IF(isEmpty(z1), isEmpty(left(z1)), right(z1), node(left(left(z1)), elem(left(z1)), node(right(left(z1)), elem(z1), right(z1))), cons(y, cons(y, z0)), cons(y, cons(y, append(z0, z1)))))
   LISTIFY(empty, cons(y, x1)) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), empty)), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), z2)), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), z1, right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(left(empty)), node(right(empty), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(z0), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(left(empty)), elem(empty), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(z0), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), right(empty), node(left(empty), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(z0), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c10(IF(isEmpty(empty), isEmpty(left(empty)), empty, node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(left(node(z0, z1, z2))), z2, node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(empty, cons(y, x1)) -> c10(IF(isEmpty(empty), isEmpty(empty), right(empty), node(left(left(empty)), elem(left(empty)), node(right(left(empty)), elem(empty), right(empty))), cons(y, x1), cons(y, append(x1, empty))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(isEmpty(node(z0, z1, z2)), isEmpty(z0), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
   LISTIFY(node(z0, z1, z2), cons(y, x1)) -> c10(IF(false, isEmpty(left(node(z0, z1, z2))), right(node(z0, z1, z2)), node(left(left(node(z0, z1, z2))), elem(left(node(z0, z1, z2))), node(right(left(node(z0, z1, z2))), elem(node(z0, z1, z2)), right(node(z0, z1, z2)))), cons(y, x1), cons(y, append(x1, node(z0, z1, z2)))))
K tuples:
   LISTIFY(empty, x1) -> c17(APPEND(x1, empty))
   LISTIFY(x0, cons(y, x1)) -> c17(APPEND(cons(y, x1), x0))
   LISTIFY(empty, cons(y, x1)) -> c17(APPEND(cons(y, x1), empty))
Defined Rule Symbols:   isEmpty_1, left_1, right_1, elem_1, append_2

Defined Pair Symbols:   APPEND_2, IF_6, LISTIFY_2

Compound Symbols:   c8_1, c19_1, c20_1, c17_1, c10_1, c11_1, c12_1, c13_1, c14_1, c15_1, c16_1, c17_2, c9_1